Hach AutoCAT 9000 Instruction Manual

Chlorine Amperometric Titrator

50081-18

50081_TTL.fm

Safety Information..................................................................................................................................................5

Specifications...........................................................................................................................................................7

Section 1 Introduction................................................................................................................................9

1.1 General Information............................................................................................................................................9

1.2 Instrument Startup Summary ..............................................................................................................................9

1.3 Unpacking.........................................................................................................................................................10

1.4 User Access Levels...........................................................................................................................................11

Section 2 Instrument Assembly............................................................................................................13

2.2 Instrument Assembly ........................................................................................................................................15

2.2.1 Attaching the Titrant Bottle Holder .........................................................................................................15

2.2.2 Connecting the Electrode Head and Accessories.....................................................................................15

2.2.3 Connecting the Titrant Bottle...................................................................................................................16

2.2.4 Assembling the Burette ...........................................................................................................................17

2.2.5 Connecting the Temperature Sensor .......................................................................................................18

2.2.6 Installing the Electrode ...........................................................................................................................19

2.2.7 Power Connection....................................................................................................................................19

2.2.8 Serial Printer and PC Connections...........................................................................................................20

Operation...............................................................................................................................................................21

Section 3 Basic Operation.......................................................................................................................23

3.1 Instrument Display and Keypad .......................................................................................................................23

3.2 AutoCAT Main Menus......................................................................................................................................24

3.2.1 How to Access the Menus........................................................................................................................24

3.2.2 Methods Menu .........................................................................................................................................24

3.2.3 Titrants Menu...........................................................................................................................................25

3.2.3.1 Changing Titrants ..............................................................................................................25

3.2.3.2 Daily Start-up .....................................................................................................................26

3.2.4 Electrodes Menu ......................................................................................................................................26

3.2.5 Cell Menu.................................................................................................................................................27

3.3 System Configuration .......................................................................................................................................27

3.3.1 Entering the Supervisor Code ..................................................................................................................27

3.3.2 Setting a User ID......................................................................................................................................27

3.3.3 Choose a Language ..................................................................................................................................27

3.3.4 Set the Time .............................................................................................................................................28

3.3.5 Set the Date ..............................................................................................................................................28

3.3.5.1 Select Optional PC Keyboard ............................................................................................28

3.3.6 Selecting the ac Power Frequency ...........................................................................................................28

3.3.7 Printer Status............................................................................................................................................29

3.3.8 Beep ON/OFF ..........................................................................................................................................29

Table of Contents

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Table of Contents

3.3.9 Rules for Routine Access Users...............................................................................................................29

3.3.10 Customizing the Station.........................................................................................................................30

3.3.11 Reset to Factory Settings........................................................................................................................30

3.3.12 Exit.........................................................................................................................................................30

3.4 Edition Mode ....................................................................................................................................................30

3.5 Using Sub-ID's..................................................................................................................................................31

Section 4 Software Setup.........................................................................................................................33

4.1 Accessing Supervisor Mode .............................................................................................................................33

4.2 Software Setup for Electrode and Temperature Sensor Installation .................................................................34

4.2.1 Software Setup for Disconnecting or Replacing Electrodes....................................................................35

4.3 Software Setup for Burette Installation ............................................................................................................36

4.3.1 Software Setup for Removing or Replacing the Burette .........................................................................37

4.4 Software Setup for Titrant Installation..............................................................................................................38

4.4.1 Software Setup for Switching or Replacing Titrants ...............................................................................39

4.5 Setting Titrant Concentration............................................................................................................................40

4.6 Obtaining the Certificate of Analysis for Hach Reagents.................................................................................41

Section 5 Collecting and Accessing Data ..........................................................................................43

5.1 Using the AutoCAT 9000 for Amperometric Methods ....................................................................................43

5.2 AutoCAT Titration ............................................................................................................................................43

5.2.1 Data Collection ........................................................................................................................................43

5.2.1.1 Current Range ....................................................................................................................43

5.2.1.2 Volume Increment .............................................................................................................44

5.2.1.3 Predose Volume .................................................................................................................44

5.2.1.4 Auto-scaling .......................................................................................................................44

5.2.2 End Point Determination..........................................................................................................................44

5.2.2.1 Manual End Point Determination (MEPD) .......................................................................45

5.2.2.2 Automatic End Point Determination (AEPD) ...................................................................45

5.2.2.3 Auto Detection ...................................................................................................................45

5.2.3 Parameters Used in the Calculation of the Analyte Concentration..........................................................45

5.2.3.1 Titrant Concentration .........................................................................................................45

5.2.3.2 Sample Volume ..................................................................................................................45

5.2.3.3 Dilution ..............................................................................................................................46

5.2.3.4 Reductant Concentration ....................................................................................................46

5.2.3.5 Reductant Volume .............................................................................................................46

5.2.4 Analysis Calculations...............................................................................................................................46

5.2.4.1 Calculation of Mean ...........................................................................................................47

5.2.4.2 Calculation of Standard Deviation (<5 replicate analyses) ...............................................47

5.2.4.3 Calculation of Standard Deviation (>5 replicate analyses) ...............................................47

5.2.5 Retrieving Analysis Results from Archives.............................................................................................48

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Table of Contents

Section 6 Calibration Procedures........................................................................................................49

PAO/5.64 mN, Amperometric Forward Titrant Calibration...................................................................................51

Iodine, Amperometric Back Titrant Calibration.....................................................................................................57

Section 7 Sampling ....................................................................................................................................63

7.1 Chlorine ............................................................................................................................................................63

7.2 Container Pretreatment .....................................................................................................................................63

7.3 Handling............................................................................................................................................................63

7.4 Samples for Back Titration ...............................................................................................................................63

Section 8 Titration Procedures.............................................................................................................65

Chlorine Dioxide

Generator Yield, Amperometric Forward Titration .............................................................................................67

Chlorine Dioxide, Amperometric Forward Titration..............................................................................................81

Free Chlorine, Amperometric Forward Titration....................................................................................................93

Total Chlorine, Amperometric Back Titration........................................................................................................99

Total Chlorine, Amperometric Forward Titration ................................................................................................105

Sulfite, Amperometric Back Titration .................................................................................................................. 111

Total Oxidants, “Quick” Two Step Amperometric Titration................................................................................119

Chlorite, “Quick” Two Step Amperometric Titration...........................................................................................127

Manual Endpoint Determination ....................................................................................................................135

Below Detectable Limit ....................................................................................................................................137

Section 9 Maintenance ...........................................................................................................................139

9.1 Instrument Maintenance .................................................................................................................................139

9.1.1 General...................................................................................................................................................139

9.1.2 Display ...................................................................................................................................................139

9.1.3 Cleaning the Instrument.........................................................................................................................139

9.1.4 Cleaning and Conditioning the Electrode ..............................................................................................139

9.2 Maintenance Intervals.....................................................................................................................................140

9.3 Replacing the Fuse..........................................................................................................................................140

Section 10 Troubleshooting ....................................................................................................................141

Appendix A Amperometric Titration Theory..................................................................................145

1.1 General Titration Theory ................................................................................................................................145

1.1.1 Redox Reactions ....................................................................................................................................145

1.1.2 Reaction Measurement...........................................................................................................................145

1.1.2.1 Forward vs. Back .............................................................................................................145

1.1.3 Determining Concentration....................................................................................................................146

1.1.3.1 Conversion Factor ............................................................................................................146

1.1.3.2 Sample Spike ...................................................................................................................147

1.2 Errors and Interferences..................................................................................................................................147

Table of Contents

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Table of Contents

1.2.1 Overview................................................................................................................................................147

1.2.2 Deposition on Electrode Surfaces..........................................................................................................147

1.2.3 Manganese Compounds .........................................................................................................................148

1.2.4 Nitrite Interference.................................................................................................................................148

1.2.5 Choice of Reductant...............................................................................................................................149

1.3 Errors Common to Total Chlorine Determinations.........................................................................................149

1.4 Shift of Endpoints Due to Sample Iodine Demand.........................................................................................151

1.5 Order of Reagent Addition .............................................................................................................................151

Appendix B Printer Installation and Setup......................................................................................153

Appendix C Replacement Parts & Accessories..............................................................................157

Appendix D Low Level Standards & Testing .................................................................................159

Appendix E AutoCAT 9000 Validation Study ................................................................................161

General Information........................................................................................................................................167

Certification..........................................................................................................................................................169

How To Order ......................................................................................................................................................171

Repair Service......................................................................................................................................................172

Warranty ................................................................................................................................................................173

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Safety Information

Please read this entire manual before unpacking, setting up, or operating this instrument. Pay particular attention to all danger and caution statements. Failure to do so could result in serious injury to the operator or damage to the equipment.

To ensure that the protection provided by this equipment is not impaired, do not use or install this equipment in any manner other than that which is specified in this manual.

Hazard Information

If multiple hazards exist, this manual will use the signal word (Danger, Caution, Note) corresponding to the greatest hazard.

DANGER Indicates a potentially or imminently hazardous situation which, if not avoided, could result in death or serious injury.

CAUTION Indicates a potentially hazardous situation that may result in minor or moderate injury.

NOTE Information that requires special emphasis.

Precautionary Labels

Read all labels and tags attached to the instrument. Personal injury or damage to the instrument could occur if not observed.

This symbol, when noted on the instrument, references this instruction manual for

operational and/or safety information.

This symbol, when noted on the product, identifies the location of a fuse or current

limiting device.

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Page 6 50081_Safety.fm

Specifications

Specifications are subject to change without notice.

Methods

Titration methods 7 embedded methods

Titration stops Automatic and manual titration termination

Titrant addition technique Incremental

Titrant calibration 4 embedded procedures

Back titration with manual reductant addition

Measuring Ranges

Current ranges 2 µA, 20 µA, 200 µA, 1 mAmp

Temperature range –10 to +100 °C (14 to 212 °F)

Temperature resolution 0.1 °C (0.18 °F)

Printout

Automatic, GLP compliant

Selectable; OFF or 80 columns

Detailed or condensed

Graphic or no graphic

Results

QC check on results with visual warning

Statistical calculations

Units

All standard units for samples/results

Titration Curve

Up to 2000 points can be stored

Storage Capacity

Global password protection for programming access

Non-volatile memory

Storage of 200 titration results

Stored parameters characterized by own ID, location, and calibration data

Embedded operating procedures for electrode and reagent exchange Automatic electrode, titrant calibration, and QC prompt

Sample List

Up to 126 data with alphanumeric ID

QC sample definition

Stirrer Platform

Magnetic stirrer 22 reproducible speeds (0 to 1100 rpm) in 50-rpm increments

Beaker volumes 5- to 400-mL

Specifications

50081_Specifications.fm Page 7

Specifications

Burette

Embedded burette stand 1

Burette volume 5- or 10-mL

ISO/FDIS 8655-3 compliant

Burette step motor 18,000 steps

UV-protected encapsulated glass syringe

Embedded operating procedures Burette exchange, air bubble removal (Flush), Rinse, Fill, and

Empty functions

Inputs/Outputs

Electrode input

Temperature input

Serial connections for printer/PC

PS/2 port for PC keyboard

Language Options

English and Spanish

General Specifications

Casing Splashproof ABS plastic.

Graphic 128 x 128-dot LCD and alphanumeric keypad

Dimensions (H x W x D) 380 x 230 x 450 mm (15 x 9 x 17¾ inch) excluding tubing

Weight 5 kg (11 lb) excluding reagent bottles

CE marking EMC directive 89/336/EED Compliant

LV directive 73/23/EEC Compliant

Power requirements 50/60 Hz (±3 Hz)

100/240 V ac (±10%)

Pollution Degree II

Overvoltage Category II

Fuses Primary, User-serviceable. Slow-blow 1.0 A, 250 V

Secondary, factory-serviceable only.

Environmental operating conditions 5 to 40 °C (41 to 104 °F) temperature range

20 to 80% relative humidity range

Specifications Page 8

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Section 1 Introduction

1.1 General Information

The AutoCAT 9000™ is an automated chlorine amperometric end point titration instrument. Its biamperometric system uses a dual platinum electrode (DPE) probe.

Hach offers amperometric methods for determining total chlorine*, free chlorine, sulfite, and chlorine dioxide in water. The chlorine dioxide procedure also provides a measurement of chlorite concentration.

Follow the steps listed in Section 1.2, Instrument Startup Summary, on page 9. After completing these steps, refer to the method calibrations and method procedures for instructions on specific analyses.

Amperometric titration theory and interferences are detailed in Amperometric Titration Theory on page 145.

1.2 Instrument Startup Summary

When you receive your AutoCAT 9000, proceed in the following order:

1. Unpack the instrument and inspect all parts for any damage that occurred during shipment. Refer to Table 1 and Figure 1 and Figure 2 on page 24.

2. Assemble the instrument following the instructions in Section 2 on page 13

3. Review Basic Operation on page 23 to familiarize yourself with the user interface

and the keypad, navigation, and command keys.

4. Set the software parameters and configure the interface following the instructions given in Section 4 Software Setup.

5. Clean and condition the electrode according to section 9.1.4 on page 139.

6. The instrument is set up and ready to perform analyses. The default titrant

concentration is adequate when using a fresh bottle of titrant but you may choose to calibrate the titrant using the procedures given in Calibration Procedures on page 49 or you can download the exact concentration of your titrant, see Obtaining the Certificate of Analysis for Hach Reagents on page 41.

7. At this time you may wish to run a few test samples to familiarize yourself with the instrument. We recommend that you use tap water to perform the Total Chlorine procedure in Titration Procedures on page 65.

8. If desired, you may choose to perform certain setup or configuration steps in Basic Operation on page 23 but they are not essential for using the instrument.

*Forward and Back titration methods are offered for the determination of Total Chlorine.

50081_Introduction.fm Page 9

1.3 Unpacking

Remove the instrument and accessories from the shipping cartons and inspect each item for damage that may have occurred during shipment. Refer to Tab l e 1 and Figure 1 on page 23 to verify that your order is complete.

Table 1 Packing List

Illustration

Item Number

Not shown 50083-00 1 AutoCAT 9000 AmperometricTitration Workstation

Not shown 18010-00 1 125 V ac power cord

1 — 1 Titrant pick-up tubing

2 50082-40 1 Delivery tubing with plastic anti-diffusion tip

3 — 1 Desiccant column

4 50087-00 1 Temperature sensor, glass, 103-mm, CINCH plug

5 50086-00 1 Metal electrode, dual platinum wire, BNC plug

6 50082-10 1 Burette stand, 5-mL, red cover

7 50082-50 1 Bottle stopper for 500 mL and 1000 mL plastic titrant bottles

8 50085-00 1 Magnetic stir bar

9 50082-60 1 Bottle stopper for 1-L glass titrant bottle

10 50088-00 1 Bottle holder

11 — 1 Stop ring for electrode head (may be pre-assembled)

12 — 1 Metal key for burette plunger adjustment

13 50082-30 1 Metal rod for electrode head support, 20-mm, with stop ring

14 50082-80 1 Bayonet electrode head macro, with support

15 50082-70 1 Fuse, slow-blow 1.0 A, (5 x 20 mm)

16 A25B600 1 Tubing from stopcock to glass cylinder

Catalog Number Qty. Product Description

Not shown 500-46H 1 Beaker, 250-mL

Not shown 1999-53 1 Titrant, PAO standard solution, 0.00564 N, 1000-mL

Not shown 28341-00 1 KI SwifTest Dispenser

Not shown 1077-60 1 Refill vial for KI SwifTest Dispenser

Not shown 14909-32 1 Buffer, pH 4, 100-mL MDB

Not shown 21553-32 1 Buffer, pH 7, 100-mL MDB

Not shown 50081-18 1 User manual

If any items are missing or damaged, please contact Hach Company or your sales representative immediately.

Page 10 50081_Introduction.fm

1.4 User Access Levels

The AutoCAT offers two user access levels:

Supervisor allows users to edit titration and analysis parameters to fit specific needs. A Supervisor-level user can also assign a password to protect the data and customized settings from inadvertent changes.

Routine

analyses.

allows users to access only the routine functions when performing the embedded

50081_Introduction.fm Page 11

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Section 2 Instrument Assembly

2.1 Operating Environment

Maintain an ambient temperature of 5–40 °C (40–104 °F) for proper instrument operation. The relative humidity should be between 20 and 80%; do not allow moisture to condense on the instrument.

Note: Retain the original packaging material. Instruments returned for service should be shipped

in the original packaging material to protect against damage during transportation.

Figure 1 Individual Parts (Refer to Table 1 for Part Descriptions)

50081_Assembly.fm Page 13

Operating Environment

Figure 2 Assembled AutoCAT 9000

Legend

Number Item Name Number Item Name

1 Magnetic Stir Bar 11 Titrant Pick-up Tubing Connection

2 250-mL Beaker 12 Desiccant Column

3 Plastic Anti-diffusion Tip 13 Electrode (BNC Connector)

4 Temperature Sensor 14 Temperature Sensor (CINCH Connector)

5 Dual Platinum Electrode 15 Bottle Stopper for Plastic Titrant Bottle

6 Support Rod for Electrode Head 16 Pick-up Tubing

7 Burette 17 Bottle Holder

8 Plastic Anti-diffusion Tip Tubing Connection 18 Stop Ring for Electrode Head

9 Burette Tubing Connection 19 Electrode Head

10 Rotating Valve 20 Keyboard PS/2 Connector

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2.2 Instrument Assembly

Perform the assembly procedures in this section and then complete the steps in Section 3 on page 23 to enter basic user information in preparation for performing analyses to comply with Good Laboratory Practices (GLP). Refer to Section 4 on page 33 for the software setup required prior to performing analyses. The software setup in Section 4 must be completed before any analyses can be performed.

2.2.1 Attaching the Titrant Bottle Holder

1. Slide the titrant bottle holder into the mounting slot located on the

bottom of the instrument housing.

Operating Environment

2. Affix holder into position by compressing the bottle holder slightly and inserting the tip into the hole located under the rim of the instrument housing.

Note: Never pick up or carry the titrator by the bottle holder.

2.2.2 Connecting the Electrode Head and Accessories

1. Thread the support rod onto the threaded stud of the stirrer platform.

Note: Never pick up or carry the titrator by the support rod.

50081_Assembly.fm Page 15

Operating Environment

2. Clip the stop ring into the locating hole on the support rod.

Note: The stop ring may be pre-assembled on the support rod.

3. Compress the clips on each side of the electrode head and slide the head onto the metal rod. Release the two clips to secure the head in place.

2.2.3 Connecting the Titrant Bottle

4. Drop the supplied magnetic stir bar into the titration beaker and place

the beaker on the titration platform.

Note: The provided stir bar has been specifically selected for use with the

AutoCAT 9000. A different stir bar may spin erratically and produce unwanted turbulence and added noise in the titration curve.

1. Place the titrant bottle into the bottle holder.

2. Thread the desiccant column onto the supplied bottle stopper.

3. Thread the appropriate bottle stopper (for 500 mL or 1000 mL titrant

bottle) onto the new titrant bottle and place it into the holder.

Page 16 50081_Assembly.fm

Operating Environment

4. Push the long section of exposed titrant pick-up tubing through the

remaining connection point on the bottle stopper and into the titrant bottle. Thread the tubing connector into the bottle stopper.

5. Thread the opposite connector into the corresponding receptacle on the

rotating valve.

Note: Make sure that the tubing is connected to the correct point on the rotating

valve as indicated by the “bottle” icon.

6. The plastic anti-diffusion tip is pre-assembled onto the beaker supply

tubing. Thread the tubing connector into the corresponding receptacle on the rotating valve.

7. Insert the plastic anti-diffusion tip into a small hole on the electrode

head. Turn the locking collar ¼-turn clockwise to lock it in place.

Note: Make sure that the tubing is connected to the correct point on the rotating

valve, indicated by the “beaker” icon.

2.2.4 Assembling the Burette

Piston Travel

1. Use the metal key to gently pull the piston plunger downward until it

protrudes slightly below the bottom of the burette.

Note: The bottom lip of the cylinder will offer only SLIGHT resistance. Do not pull

the plunger out completely. It it is inadvertently removed it may be carefully pushed back into the cylinder. After reinsertion, closely monitor the integrity of the seals after titrant is installed.

2. Place the burette on a flat surface and press the burette downward until

the piston shaft is flush with the bottom of the burette.

Note: Piston position is essential to proper instrument operation. Refer to the

illustration (left) for the correct position.

50081_Assembly.fm Page 17

Operating Environment

3. Place the burette on the burette stand in position A then slide the burette from position A to position B.

Note: Inspect the alignment of the

piston with the plunger shaft. Ensure that they are properly engaged as displayed in the illustration to the right.

4. Turn the burette ¼-turn clockwise to engage the locking tabs with the burette stand and lock the burette into position.

5. Thread the connectors of the remaining section of tubing into the top of the burette and into the corresponding receptacle on the rotating valve.

Note: Ensure that the tubing is connected to the correct point on the rotating

valve as indicated by the “burette” icon.

2.2.5 Connecting the Temperature Sensor

1. Remove the protective cap from the temperature sensor.

2. Insert the temperature sensor into a remaining small hole on the

electrode head.

3. Turn the sensor ¼-turn clockwise to lock the collar in place.

4. Connect the cable to the CINCH connector on the back of the

instrument (see Figure 3 on page 19).

Page 18 50081_Assembly.fm

2.2.6 Installing the Electrode

1. Remove the protective cap from the electrode.

2. Insert the electrode into a large hole (opposite the plastic anti-diffusion

tip) on the electrode head.

3. Turn the electrode ¼-turn clockwise to lock the collar in place.

4. Connect the cable to the BNC connector on the back of the instrument

(see Figure 3 on page 19).

Note: The electrode must be installed opposite the plastic anti-diffusion tip to

allow maximum mixing of the titrant before the reaction is sensed by the electrode.

Figure 3 AutoCAT 9000 Workstation Cable Connections

Operating Environment

Legend

Number Item Name

1 PC/Printer

2.2.7 Power Connection

A UL/CSA-approved 125-V ac power cord (Cat. No. 18010-00) is supplied with the North American AutoCAT 9000 models.

To power North American AutoCAT 9000 models with 230 V ac, replace the supplied 125-V ac power cord with a UL/CSA approved 230-V ac power cord. See section Section 3.3.6 Selecting the ac Power Frequency on page 28 for configuration settings.

Plug the power cord into the back panel of the instrument and connect the power cord to the proper outlet. See Figure 3.

2Local

3Electrode

4 Temperature Sensor

5 Power

6 Fuse Access

7 ON/OFF Switch

After assembly is complete, perform the steps in Section 3 on page 23 to enter basic user information in preparation for performing analyses to comply with Good Laboratory Practices. Refer to Section 4 on page 33 for the software setup required prior to performing analyses. The software setup in Section 4 must be completed before any analyses can be performed.

50081_Assembly.fm Page 19

Operating Environment

2.2.8 Serial Printer and PC Connections

Note: Use of the specified or equivalent shielded cable is mandatory for proper protection from electromagnetic interferences.

Connect the AutoCAT 9000 Workstation to a personal computer (PC) using the optional computer interface serial cable (Cat. No. A95P201). The cable provides a direct connection between the AutoCAT 9000 Workstation and the 9-pin “D” connector used for the serial port found on most personal computers. If your computer has a 25-pin D connector, use a 9-pin to 25-pin adapter (available at many computer supply stores).

Connect the AutoCAT 9000 to an existing printer using the optional printer interface serial cable (Cat. No. A95P201). The printer must have the following characteristics:

• 80 characters

• RS232C: 9600 baud, 8 data bits, no parity, 1 stop bit

• Must allow printing of tables

Hach offers an optional printer (Cat. No. A70P021) for use with the AutoCAT 9000. See Appendix B Printer Installation and Setup on page 153.

Page 20 50081_Assembly.fm

Operation

DANGER

Handling chemical samples, standards, and reagents can be dangerous. Review the necessary Material Safety Data Sheets and become familiar with all safety procedures before handling any chemicals.

DANGER

La manipulation des échantillons chimiques, étalons et réactifs peut être dangereuse. Lire les Fiches de Données de Sécurité des Produits (FDSP) et se familiariser avec toutes les procédures de sécurité avant de manipuler tous les produits chimiques.

PELIGRO

La manipulación de muestras químicas, estándares y reactivos puede ser peligrosa. Revise las fichas de seguridad de materiales y familiarícese con los procedimientos de seguridad antes de manipular productos químicos.

GEFAHR

Das Arbeiten mit chemischen Proben, Standards und Reagenzien ist mit Gefahren verbunden. Es wird dem Benutzer dieser Produkte empfohlen, sich vor der Arbeit mit sicheren Verfahrensweisen und dem richtigen Gebrauch der Chemikalien vertraut zu machen und alle entsprechenden Materialsicherheitsdatenblätter aufmerksam zu lesen.

PERICOLO

La manipolazione di campioni, standard e reattivi chimici può essere pericolosa. La preghiamo di prendere conoscenza delle Schede Techniche necessarie legate alla

Operation

50081_OperationStop.fm Page 21

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Section 3 Basic Operation

3.1 Instrument Display and Keypad

The instrument display and keypad form an interactive user interface for the AutoCAT 9000 allowing the user to view data, select options, and enter commands.

Individual screens define certain keystrokes at the bottom of the display. The horizontal scroll bar indicates the relative status of the page being displayed. Use the

LEFT keys to scroll the screens.

Figure 1 Display and Keys

RIGHT and

Legend

Number Item Name Number Item Name

1 Display 5 Print Key

2 Keypad 6 Stop Key

3 Delete Key 7 Check Mark Key

4 Escape Key 8 Navigation Keys (LEFT, RIGHT, UP, DOWN)

• The keypad is used to enter alpha and numeric characters and punctuation. Press and

hold a key to cycle through the series of characters assigned to it. Choose a character by pressing and holding the key until the desired character is displayed, then release the key. Press and hold to scroll from uppercase to lowercase letters. Delete the character displayed above the screen cursor by pressing the

DEL key.

• The navigation keys include a CHECK MARK and four directional keys (LEFT, RIGHT,

, DOWN) Use these keys to navigate within menus, move cursors, and select

between options. The confirm displayed information. The

CHECK MARK key is generally used to select an option or

CHECK MARK key is also used to stop the data

collection process during titration.

• The remaining keys on the keypad are labeled ESC, PRINT, and STOP.

• The ESC key is generally used to exit the currently displayed screen and return to

the previously displayed screen.

Basic Operation

50081_Operation.fm Page 23

Basic Operation

• The PRINT key sends titration and calibration analysis results to the printer.

• The STOP key is an emergency stop and is used to interrupt the current operation

3.2 AutoCAT Main Menus

Figure 2 Main Menu

Results can be printed either during the method procedure or later from the GLP archives.

Note: Curve and Line Fit printer parameters can only be utilized when printing during a

method procedure—not from the GLP archives.

or exit an embedded method. If an analysis is interrupted, the AutoCAT 9000 will prompt the user to resume or end the analysis. All data for the analysis will be lost if it is ended prior to completion. the

STOP key is also used to access the Setup menu from the Methods menu

(press and hold for approximately three seconds).

Legend

Number Item Name

1 Title Bar

2 Selected Menu Item

3 Available Menu Items

4 Cell Tab

5 Electrode Tab

6 Reagents Tab

7 Methods Tab

3.2.1 How to Access the Menus

• Press UP or DOWN key to scroll vertically and highlight various items within

currently displayed menus. To select, highlight the desired item and press the

CHECK MARK to confirm. Selections can also be made by pressing the corresponding

number (

1 – 6, if available), to the right of the selection; this feature provides quick,

one-step access.

• Individual menus define certain keystrokes at the bottom of the display. The

horizontal scroll bar indicates the relative status of the screen(s) being displayed.

Note:Press the RIGHT or LEFT key to tab horizontally between Methods, Titrants, Electrodes,

and Cell menus.

3.2.2 Methods Menu

The Methods menu provides access to the embedded procedures, adjustable parameters, and stored titration analyses results. Major components are explained below.

• Title bar—displays the instrument name, current time, and current "method" name,

along with the Sub-ID.

• Run method—initiates the method currently selected.

• Select method—allows selection of the method(s) for analyses.

• Display method—(available in Routine Mode) allows the user to change the

Method or Sub-ID.

Basic Operation Page 24

50081_Operation.fm

• Method library—(available in Supervisor Mode) contains all of the adjustable

• GLP-Archives—provides access to the Good Laboratory Practice (GLP) tables, the

• Method Tab—is an animated icon that becomes active when a titration/calibration is

Note:From the Methods menu, adjust the contrast of the display by pressing 7 to lighten,

3.2.3 Titrants Menu

The Titrants menu provides access to the embedded calibration procedures, adjustable parameters, stored calibration results, and burette functions.

• Title bar—displays Titrants

• Calibrate/Enter titrant conc.—determines the concentration of the titrant by

• Install titrants—allows the user to install or replace the titrants in the selected

• Check titrants—allows the user to verify the parameters of the titrant used in the

• Titrant library—contains all of the adjustable calibration parameters. Supervisors

• GLP-Archives—provides access to the Good Laboratory Practice (GLP) tables and

• Burette functions—allows the user to fill, empty, flush, rinse, and replace the

• Titrants tab—displays one of four titrant status icons, see Table 1.

Basic Operation

method parameters. Those with supervisor access can edit, reset, and delete method parameters to suit specific needs.

stored method analysis results, and global variables.

being performed.

and 0 to darken.

running a calibration or calibration sequence. Alternatively, the concentration can be input manually on the alphanumeric keypad.

method.

selected method.

can choose to have the titrant concentration input manually or determined through embedded calibration.

display the stored titrant calibration results.

burette.

Table 1 Titrant Status Icons

Sunny Icon—the titrant calibration or manual entry of the titrant concentration has been performed satisfactorily for the current titrant.

Cloudy Icon—either the titrant calibration should be performed within 24 hours, or the titrant will expire in less than one week.

Stormy Icon—the titrant calibration or the titrant in the system has expired, the calibration has failed to satisfy the user-programmed acceptance limits, or the installed titrant and selected method are incompatible.

Question Mark—a problem exists within the method parameters for the titrant. Supervisory level access is required.

3.2.3.1 Changing Titrants

The auto-flush routine takes 60 seconds and uses 10–12 mL of titrant. This function provides a thorough flush and should be used when changing to a different titrant.

1. From the Titrant menu, press

2. Press

50081_Operation.fm Page 25

3 to begin the flush cycle. Allow the cycle to run to completion.

6 to access Burette Functions.

Basic Operation

3.2.3.2 Daily Start-up

Even though the delivery tube has an anti-diffusion tip, titrant in the delivery line can be slightly diluted or contaminated when electrodes are in storage solution (tap water, or water with weak bleach solution). Bubbles may form due to titrant outgassing. Diluted titrant and air bubbles can be purged with a manual empty/fill cycle prior to first run on a daily basis, or after a lengthy idle period.

A manual flush cycle uses only 5 mL of titrant.

1. From the Titrant menu, press

2. Press

3. When the burette empties at least half of its contents, press

the burette.

3.2.4 Electrodes Menu

The Electrodes menu provides access to the electrode cleaning and conditioning procedure, adjustable parameters, direct measurement, and electrode/temperature sensor functions.

• Title bar—displays Electrodes.

• Method—indicates the method currently selected.

• Connect electrodes—allow the user to connect the electrode.

• Disconnect electrode—allows the user to disconnect the electrode.

• Replace electrode—allows the user to replace the electrode.

• Check electrodes—identifies and displays the parameters of the electrode used in a

method.

• Electrode cleaning—guides the user through the electrode cleaning and

conditioning procedure.

• Display measurement—performs current measurement or displays the temperature,

based on the selected electrode.

• Electrodes tab—displays one of three electrode status icons, see Ta b l e 2.

6 to access Burette Functions.

2 to empty the burette.

STOP, then press 1 to refill

Basic Operation Page 26

Table 2 Electrode Status Icons

Sunny Icon—the electrode has been correctly installed.

Stormy Icon—there is a problem with the electrode installation.

Question Mark—a supervisory level problem exists within the method parameters for the installed electrode.

50081_Operation.fm

3.2.5 Cell Menu

The Cell menu provides access to stirrer function and speed increment adjustment.

• Title bar—displays Cell.

• Stirring—allows the user to switch the stirrer On or Off.

• Speed—allows the user to adjust the internal stirring speed from 100 to 1100

revolutions per minute (rpm) in 50-rpm increments.

Note:The default stir speed is 250 rpm.

• Cell tab—displays an animated icon that indicates the stirrer status.

3.3 System Configuration

3.3.1 Entering the Supervisor Code

Note:There is no factory default code. To proceed in supervisory mode, a user-defined code

must be entered.

1. Turn the instrument ON. From the Methods Menu, press and hold the STOP key for approximately three seconds to enter the Setup Menu.

2. Input the Supervisor Code input up to 10 digits consisting of any combination of numbers, upper- and lower-case letters, or symbols. Press the this code. All future access to the Setup menu will require the input of this casesensitive code.

Note:To establish the Supervisor code, see Accessing Supervisor Mode on page 33.

Basic Operation

CHECK MARK to record

3. Press the CHECK MARK to confirm.

Note:If already operating in Supervisor mode, the AutoCAT 9000 will not request the supervisor

code to access the Setup menu.

4. Select the Configuration Menu and proceed to Section 3.3.2.

3.3.2 Setting a User ID

Select whether or not a User ID will be required:

1. Highlight User ID.

2. Press the

3. Press the

No (to disable the User ID function).

4. Press the Configuration Menu.

3.3.3 Choose a Language

1. Highlight Language.

2. Press the

3. Press the

French, or Spanish).

4. Press the Configuration Menu.

CHECK MARK to confirm.The title bar will display User ID.

UP or DOWN key to toggle between Yes (to enable the User ID function) and

CHECK MARK to validate the highlighted selection and return to the

CHECK MARK to confirm.The title bar will display Language.

UP or DOWN key to highlight one of the available languages (English,

CHECK MARK to accept the highlighted selection and return to the

Basic Operation

50081_Operation.fm Page 27

Basic Operation

3.3.4 Set the Time

3.3.5 Set the Date

1. Highlight Time.

2. Press the

3. Input the hour (00 to 23). Press the

4. Input the minutes (00 to 59). Press the

5. Input the seconds (00 to 59). Press the

CHECK MARK to confirm the selection.

RIGHT key to scroll to minutes.

RIGHT key to scroll to seconds. CHECK MARK to validate and return to the

Configuration Menu.

Note:Press the LEFT arrow to access a previous field.

1. Highlight Date.

2. Press the

3. Input the day (1 to 31). Press the

4. Select the month using the

5. Input the year (2000 to 2069). Press the

CHECK MARK to confirm the selection.

RIGHT key to scroll to Month.

UP or DOWN key. Press the RIGHT key to scroll to Year.

CHECK MARK to validate and return to the

Configuration Menu.

Note:Press to access a previous field.

3.3.5.1 Select Optional PC Keyboard

Select an optional, external keyboard to connect to the 6-pin PS/2 receptacle located on the right hand side, bottom edge of the instrument.

1. Scroll to highlight PC Keyboard.

2. Press the

3. Press the

CHECK MARK to confirm the selection.

UP or DOWN key Highlight English (US) for a standard, QWERTY-type

keyboard.

4. Press the

Note:When using the optional keyboard, press F12 to enter the Setup menu. This is done by

CHECK MARK to validate and return to the Configuration Menu.

pressing the Fn and F2 keys simultaneously.

3.3.6 Selecting the ac Power Frequency

Select the ac power supply frequency (50 Hz/230 V ac or 60 Hz/115 V ac) to optimize instrument operation for regional power.

1. Highlight AC Power Frequency.

2. Press the

3. Press the

Note: The default, 60-Hz /125-V ac setting is required for operation in the U.S. and Canada.

CHECK MARK to confirm the selection.

UP or DOWN key to highlight the desired setting.

Basic Operation Page 28

4. Press the CHECK MARK to validate and return to the Configuration Menu.

50081_Operation.fm

3.3.7 Printer Status

See Printer Installation and Setup on page 153 for the printer installation procedure.

Basic Operation

1. Select the printer status using the

Press the

2. Press the the

Note:If the printer option is enabled, a printer must be connected to the instrument. If no printer

CHECK MARK to confirm the selection.

UP or DOWN key. With the desired setting highlighted, press

CHECK MARK to validate and return to the Configuration Menu.

is connected, an error message will be displayed and the instrument will try to detect a printer for extended periods of time.

3.3.8 Beep ON/OFF

This selection toggles the ON/OFF status of the alarm beeper. If enabled, the AutoCAT will emit an audible beep to alert the user to analysis completion, titrant expiration, etc.

1. Highlight Beep.

2. Press the

3. Press the

4. Press the

CHECK MARK to confirm the selection.

UP or DOWN key CHECK MARK to validate and return to the Configuration Menu.

3.3.9 Rules for Routine Access Users

1. Access the Setup menu.

2. Select Access Routine Mode.

DOWN key to highlight Printer.

Supervisor defines which operations can be ignored in routine mode. Configure

The Demand and Alarm parameters for Titrant calibration by highlighting the desired selection then pressing The configuration options are as follows:

Demand: Unlocked

The routine user can ignore the demand for titrant calibration and continue the measurements.

Demand: Locked

The routine user must either calibrate the titrant or input a new titrant concentration before continuing the measurements.

Alarm: Unlocked

The routine user can accept a titrant calibration even if the analysis result lies outside the acceptance range specified by the method.

Alarm: Locked

The routine user must repeat the titrant calibration when the analysis result lies outside the acceptance range specified by the method.

Basic Operation

50081_Operation.fm Page 29

Basic Operation

3.3.10 Customizing the Station

From the Setup menu, select Customize.

1. Highlight Station.

2. Input the desired station information.

3. Press the

CHECK MARK to confirm.

4. Individually highlight text lines 1–4 (below Laboratory).

5. Input text (up to 32 characters x 4 lines). After the entry of each line, press

CHECK MARK to validate and move to the next line.

the

6. Press

Note:A typical workstation is defined with a name, user(s) name(s), address, contact information,

ESC to return to the Setup menu.

etc.

3.3.11 Reset to Factory Settings

This option will return the AutoCAT parameters to factory defaults. All user-installed information, archived analysis results, method/titrant library changes, etc., will be erased. Only the burette parameters will remain in memory.

1. From the Setup menu, select Reset to Factory Settings.

2. Press the

CHECK MARK or Press 1 to confirm the selection and return to the Setup

menu.

3.3.12 Exit

This selection allows the user to exit the Setup menu and return to the main menus with either supervisor or routine access.

3.4 Edition Mode

1. From the Setup menu, select Exit.

2. Highlight Return In Mode. Press the

3. Press the

UP or DOWN key. Press the CHECK MARK to validate.

CHECK MARK to confirm the selection.

4. Select Confirm. The Methods menu will be displayed.

The AutoCAT 9000 edition feature allows the user to multi-task by viewing/editing parameters during embedded procedure timer and data collection periods. This can only be accessed during data collection, timers, and on screens where Esc is not defined.

1. To access the Edition feature (during a titration/calibration):

a. Press

ESC.

b. Select Edition.

The user can now access parameters and make any desired changes.

2. To return to the embedded procedure:

a. Press

ESC.

b. Select Analysis Window.

Note:Access to parameters is governed by the access mode (Supervisor/Routine).

Basic Operation Page 30

50081_Operation.fm

3.5 Using Sub-ID's

Basic Operation

Note:Any changes made with the Edition feature will take effect on subsequent procedures— not

on the current sample titration.

The AutoCAT 9000 allows the user to store optimized parameters for up to three Sub-IDs for each method. The user can create these Sub-IDs with parameters optimized for a specific point of the process they need to monitor.

This eliminates the need for operators to change the titration parameters for samples from different points of their process: they need only to select an appropriate Sub-ID.

1. To change the Sub-ID in Routine Mode, select Display Method on the Main Menu screen. In Supervisor Mode, select Method Library on the Main Menu screen.

2. From this screen, both the Method and the Sub-ID can be changed. To change the Method or the Sub-ID select ID or Sub-ID respectively.

3. Initially these Sub-IDs have identical default parameters, and are simply named A, B, C. The user can assign names to these Sub-IDs, such as Influent, Effluent, Low, Medium, High, Tap 1, Tap 2, Pre-Dechlor, etc.

4. The individual parameters for a Sub-ID (Predose, Max. Volume, Increment, and Current Range) can be changed by selecting any of the titrations listed for the method.

Note: More information on the effects of changing these parameters can be found in Collecting and Accessing Data (page 43).

5. To return to the Main Menu press ESC.

Basic Operation

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Basic Operation

Basic Operation Page 32

50081_Operation.fm

Section 4 Software Setup

The AutoCAT 9000 requires both assembly and software setup before any calibration or titration analyses may be performed. The software setup labels the installed hardware/titrant for use with the embedded procedures. In this section the supervisor-level user will perform, in order, the following setup tasks:

1. Input the supervisor code and operate in supervisor mode.

2. Software setup for installing the electrode and temperature sensor.

3. Software setup for installing the burette.

4. Software setup for installing the titrant.

5. Input the titrant concentration value.

After the initial software setup, the user will seldom need to install the burette, electrode, or temperature sensor. The titrant will need to be installed only when replacing the titrant bottle or switching to a method requiring a different titrant.

Use the following procedures to set up the AutoCAT 9000 titrator software.

4.1 Accessing Supervisor Mode

1. Turn the instrument ON

or, if already in operation, access the Methods menu (see Section 3.2.1 on page 24).

Press and hold the for approximately 3 seconds to enter the Setup menu.

Note: The Total Cl2 - Fwd. procedure has been chosen for demonstration purposes because it utilizes the provided PAO titrant.

50081_SoftwareSetup.fm Page 33

STOP key

2. Enter or set the

supervisor code by using the key pad to input any combination of numbers, upper- and lower-case letters, or symbols (up to 10 digits).

Note: There is no factory default code. To proceed in supervisory mode, a user-defined code must be entered.

Note: To initially set the Supervisor Code, refer to the instructions in Section 3.3.1 on page 27. All future access to the Setup menu will require the user to input this case-sensitive code.

3. Press the CHECK MARK

to validate, and enter the Setup menu.

4. Press 5 to Exit.

Software Setup

5. Press the CHECK MARK

to change the Return In Mode.

4.2 Software Setup for Electrode and Temperature Sensor Installation

6. Highlight Supervisor.

Press the validate.

CHECK MARK to

7. Press 1 to select

Confirm Mode.

8. The AutoCAT is now

operating in Supervisor mode. The Methods menu will be displayed. Proceed to Software Setup for

Electrode and Temperature Sensor Installation.

1. From the Methods

menu (see How to Access the Menus on page 24), use

the

RIGHT and LEFT keys to

tab to the Electrodes menu.

Software Setup Page 34

2. Press 1 to select

Connect Electrodes.

3. Highlight S/N.

Press the input or change.

CHECK MARK to

4. Use the alphanumeric

keypad to input the last 10 digits of the electrode serial number (located on the electrode cable).

Press the validate.

CHECK MARK to

50081_SoftwareSetup.fm

Software Setup

5. Press 1 to select confirm

and proceed to temperature sensor installation.

6. Highlight S/N.

Press the input or change.

CHECK MARK to

7. Use the alphanumeric

keypad to input the last 10 digits of the sensor serial number (located on the electrode cable).

Press the

CHECK MARK to

validate.

4.2.1 Software Setup for Disconnecting or Replacing Electrodes

To disconnect the temperature sensor and electrode:

1. Press

2. Confirm by pressing the

3. Remove the probes.

To replace the temperature sensor and/or electrode:

1. Press 3 to select Replace Electrode.

2. Highlight ID, press the

2 to select Disconnect Electrode.

CHECK MARK (for each probe).

CHECK MARK to confirm.

8. Press 1 to select

Confirm and complete the installation and return to the Electrodes menu.

Proceed to Software Setup for Burette Installation on page 36.

3. Highlight either 50086-00 (electrode), or 50087-00 (temperature sensor).

4. Press the

5. Press

CHECK MARK to validate.

1 to confirm.

6. Remove the probe.

7. Install the replacement probe.

8. Input the serial number of the replacement probe.

9. Press

50081_SoftwareSetup.fm Page 35

1 to confirm.

Software Setup

4.3 Software Setup for Burette Installation

1. Use navigation keys to

tab to the Titrants menu.

5. Highlight

Burette Volume. Press the

CHECK MARK to input or

change.

2. Press 6 to select

Burette Functions.

6. Highlight the desired

burette.

Note: The default software setting is 5-mL.

Press the CHECK MARK to validate.

3. Press 5 to select

Install Burette.

7. Highlight S/N. Press the

CHECK MARK to input or

change.

4. The burette will

automatically move to the install position.

8. Use the alphanumeric

keypad to input the burette serial number (located on the bottom edge of the burette).

Press the validate.

CHECK MARK to

Software Setup Page 36

50081_SoftwareSetup.fm

Software Setup

9. Verify the burette

information.

Press

1 to confirm.

10. Install the burette if not

already installed. See

Section 2.2.4 Assembling the Burette on page 17 for

11. The burette will

automatically reposition after the install.

complete instructions.

Press the

CHECK MARK to

validate.

4.3.1 Software Setup for Removing or Replacing the Burette

To remove the burette:

1. Press

2. Press the

3. Follow the embedded procedure (including the purge and rinse cycles).

4. Remove the burette.

To replace the burette:

1. Press

2. Press

3. Highlight Burette Volume and press the

4. Input the replacement burette volume and press the

6 to select Remove Burette.

CHECK MARK to confirm.

5 to select Replace Burette.

1 to confirm.

12. Press Esc to return to

the Titrants menu. Proceed to Section 4.4 on page 38.

Note: When the burette installation is complete the Replace Burette and Remove Burette options will be displayed.

CHECK MARK to confirm.

CHECK MARK to validate.

5. Highlight Serial Number and press the

6. Input the replacement burette serial number and press the

7. Press

1 to confirm.

8. Remove the burette and press the

9. Install the replacement burette and press the

50081_SoftwareSetup.fm Page 37

CHECK MARK to confirm.

CHECK MARK to validate.

CHECK MARK to confirm.

Software Setup

4.4 Software Setup for Titrant Installation

1. From the Titrants menu,

2 to select Install

press Titrants.

5. Highlight Expiration.

Press the input or change.

CHECK MARK to

2. Press 1 to select

Titrants Setup.

6. Use the alphanumeric

keypad to input the month and year of the titrant expiration date (located next to the barcode on the titrant bottle).

Press the validate.

CHECK MARK to

3. Highlight Lot no.

Press the input or change.

CHECK MARK to

7. Verify the titrant

information. Press confirm.

1 to

4. Use the alphanumeric

keypad to input or change the titrant lot number— located next to the barcode on the titrant bottle.

Press the

CHECK MARK to

validate.

8. Press 2 to select

No Rinse.

Note: Initial installation does not require a burette rinse; however, it is highly recommended for titrant replacement or exchange.

Software Setup Page 38

50081_SoftwareSetup.fm

Software Setup

9. Connect the tubing and

install the titrant bottle if it is not already installed. See

Section 2.2.3 Connecting the Titrant Bottle on page 16

for complete instructions.

Place the 250-mL beaker onto the stirrer platform.

Press the confirm.

CHECK MARK to

10. The burette will

complete several cycles to purge air bubbles in the system.

Verify that connections are not leaking and that air is not present in the delivery tubing.

Lightly tap the tubing during the flush to dislodge and

11. The titrant has been

successfully installed. Discard the waste titrant and clean and pretreat the beaker before performing another titration.

Press

ESC to return to the

Titrants menu.

Proceed to Setting Titrant

Concentration on page 40. displace any trapped bubbles.

Note: DO NOT stop the flushing process before it is complete or the titrant installation procedure will not be completed. Flushing will take approximately 60 seconds.

4.4.1 Software Setup for Switching or Replacing Titrants

Note: AutoCAT will display an error message if the method and titrant are incompatible. If this message appears, the user must switch titrants to accommodate the method.

1. Access the Methods menu (see Section 3.2.1 on page 24)

2. Press

3. Highlight the desired method, press the

4. Use the

5. Press

6. Press

7. Press

8. Highlight Lot No. and press the

9. Input the lot number for the required titrant, press the

10. Highlight Expiration, press the

11. Input the Expiration date for the required titrant, press the

Note: If replacing depleted titrant, the embedded procedure will automatically begin here.

2 choose Select Method.

CHECK MARK to validate.

RIGHT and LEFT keys to move to the Titrants menu.

2 to select Install Titrants.

1 to select Titrants Setup to replace titrants (for a new method), or

press

2 to select Bottle Exchange to replace depleted titrant with a new bottle.

1 to confirm.

CHECK MARK to confirm.

CHECK MARK to validate.

CHECK MARK to confirm.

CHECK MARK to validate.

12. Press 1 to confirm.

13. Ensure that the correct change will be made.

Software Setup

50081_SoftwareSetup.fm Page 39

Software Setup

4.5 Setting Titrant Concentration

14. Press 1 to confirm.

15. Select Rinse Before Replacing and follow the embedded method procedure.

1. From Titrants menu,

1 to select

press Calibrate/Enter Titrant Conc.

5. Highlight User and

press the to input or change the user ID.

CHECK MARK

2. Highlight PAO 5.64mN

(or another method) and press the

CHECK MARK to

view the list of available titrants for the chosen procedure.

Note: 5.64 mN is equivalent to

0.00564 N.

6. Use the alphanumeric

keypad to input the user ID.

Press the validate.

Note: The user ID may be any combination of alphanumeric characters up to 16 characters in length.

CHECK MARK to

3. Highlight the titrant

identifier (PAO 5.64mN in

this example) and press the

CHECK MARK to validate.

Note: The AutoCAT 9000

automatically stores installed

titrants for later concentration

updates or calibrations.

7. Verify the user ID and

press

1 to confirm.

4. Press 1 to select Enter

Titrant Concentration.

8. Highlight Titrant Conc.

and press the to input or change the concentration.

CHECK MARK

Software Setup Page 40

50081_SoftwareSetup.fm

Software Setup

9. Use the alphanumeric

keypad and navigation keys to input or change the titrant concentration.

Press the validate.

Note: Product lots differ slightly in concentration. See Section

4.6 Obtaining the Certificate of Analysis for Hach Reagents.

CHECK MARK to

10. Highlight Certificate

No. and press the

MARK to input/change.

CHECK

11. Use the alphanumeric

keypad to input the titrant

certificate number.

Press the

validate.

Note: This supports the

GLP archives for titrant

install/calibration, but is not

required for operation.

CHECK MARK to

4.6 Obtaining the Certificate of Analysis for Hach Reagents

Using an internet connection, download the “Certificate of Analysis” (COA) for any Hach Company reagent or titrant to obtain the exact concentration of any unopened bottle of Hach titrant or standard solution.

1. Go to www.hach.com.

2. Click on “Information Central”.

3. Click on “Certificate of Analysis Download”.

12. Verify the titrant

concentration and certificate number.

Press

1 to confirm and return

to the Titrants menu.

Initial software setup is now complete for the Total Cl2 Fwd. method.

The Catalog Number and Lot Number, located on the label of your Hach reagent bottle, will be requested.

Software Setup

50081_SoftwareSetup.fm Page 41

Page 42 50081_SoftwareSetup.fm

Section 5 Collecting and Accessing Data

5.1 Using the AutoCAT 9000 for Amperometric Methods

The following analysis procedures, based on Standard Methods, are embedded directly in the instrument software:

• Forward titration for free chlorine

• Forward titration for total chlorine

• Back titration for total chlorine

• Forward titration for chlorine dioxide

Hach sells pre-standardized titrants, prepared according to Standard Methods, for both forward and back titrations. The 0.00564 N phenylarsine oxide titrant (Cat. No. 1999-53) has a shelf life of >1 year in the unopened bottle. The unopened 0.0282 N Iodine Standard Solution titrant (Cat. No. 23333-53) is stable for 6 to 12 months.

Periodically recalibrate the titrants after opening to ensure accuracy. Dispense reagents directly from the product bottle to eliminate contamination from transferring them to separate containers.

5.2 AutoCAT Titration

AutoCAT 9000 functions can be separated into three categories: (1) data collection, (2) end point determination, and (3) calculation. Each category is described in the sections below.

5.2.1 Data Collection

The AutoCAT displays the titration curve (current (µA) vs. titrant volume (mL)) graphically in real time, as it dispenses titrant and measures the current. After the titration is complete, the user can choose between a fully automated or manual routine to determine the end point. Following end point determination, the AutoCAT 9000 automatically calculates the analyte concentration.

The titration curve is constructed by plotting the measured current as a function of the volume of titrant added. Several parameters, which must be set prior to data collection, are available to control the data collection process. These parameters include the (1) current range, (2) volume increment, (3) predose volume, and (4) Auto-scaling.

5.2.1.1 Current Range

Current Range allows the user to set the maximum current (in µA) expected for a particular titration. The AutoCAT 9000 allows four possible settings (2 µA, 20 µA, 200 µA, and 1 mA) for the current range. The default setting (20 µA) setting is adequate for most purposes. The 2 µA setting is recommended when analyzing samples with concentration less than 0.600 mg/L Total Chlorine.

Note:The 200-µA and 1-mA settings are available for experimental use, and are not

recommended for most titrations.

Collecting and Accessing Data

50081_AutomatedTitration.fm Page 43

Collecting and Accessing Data

5.2.1.2 Volume Increment

The AutoCAT 9000 delivers titrant to the sample solution in discrete volume increments. During data collection, the AutoCAT 9000 injects one volume increment of titrant solution into the sample once every 3 seconds. The volume increment is an adjustable parameter that controls the volume (mL) of titrant dispensed for each addition. The smallest increment setting is 0.0003 mL.

In general, for forward titrations, a reasonable volume increment can be calculated based on the estimated analyte concentration (in mg/L) by dividing the end point volume in milliliters (numerically equivalent to the chlorine concentration when using

0.00564 N PAO as a titrant) by the number of points to be collected before the end point.

For example, if you wish to collect 50 points before the end point then the appropriate volume increment would be given by the following equation:

Volume Increment (mL)

A table is provided in each embedded method procedure to help determine the appropriate volume increment to use for data collection.

5.2.1.3 Predose Volume

Predose defines a volume of titrant added to the sample prior to data collection.

If 1.50 mL of titrant is required to reach the end point, the entire titration can be run using a 0.03 mL volume increment and no predose. Alternatively, a titration can run using a

0.01 mL volume increment and a 1.00 mL predose. In this case 1.00 mL of titrant is added prior to data collection and the final 0.50 mL is delivered during data collection. The same number of points will be collected and the same amount of time will be required. In the first titration a 20 µA current range will be required to avoid “clipping” the top of the titration curve. A 2 µA current range may be used in the second case.

5.2.1.4 Auto-scaling

The AutoCAT 9000 has an auto-scaling feature. When Auto-scaling is enabled the AutoCAT 9000 will attempt to set the current range and volume increment automatically. This feature is useful for titration of samples containing over 25 ppb total chlorine. Autoscaling is less useful for free chlorine titrations and cannot be used with back titrations. Auto-scaling can be used with or without a titration predose.

(Estimated Chlorine Concentration (mg/L))

----------------------------------------------------------------------------------------------------------------=

5.2.2 End Point Determination

Collecting and Accessing Data Page 44

Two associated parameters, No. points before EP and Fraction before EP, become available when Auto-scaling is activated.

The No. points before EP sets the approximate number of points desired before the end point.

The Fraction before EP sets the fraction of the total number of points collected. For example if the fraction is set to “0.50” then approximately 50% of the data points are collected before the end point and 50% afterwards.

The AutoCAT9000 incorporates two routines for end point determination. Both routines (described in Section 5.2.2.1 and 5.2.2.2) attempt to determine the volume of titrant needed to reach the break in the titration curve.

50081_AutomatedTitration.fm

Collecting and Accessing Data

5.2.2.1 Manual End Point Determination (MEPD)

MEPD requires the user to manually position the cursors on the instrument display to define separate linear regions of the titration curve on each side of the end point (i.e., the break in the titration curve). When selecting line segments, it is generally advisable to select points closer to the end point of the titration, and to avoid, as much as possible, “noisy” sections of the curve. Select a pair of lines that intersect as near as possible to the break in the titration curve. After the linear regions have been selected, the linear least squares regression lines are fit through all the points between each pair of cursors. The intersection of the two regression lines determines the end point. More guidelines for Manual End Point Determination can be found on page 135.

5.2.2.2 Automatic End Point Determination (AEPD)

AEPD allows the AutoCAT 9000 to search for a pair of intersecting lines that best fit the titration curve. The end point is determined from the intersection of the two best-fit lines.

5.2.2.3 Auto Detection

Normally, when a user runs an analysis on the AutoCAT 9000, the instrument will go directly from data collection to the zoom window. The instrument will stop in the zoom window, allowing the user to select the desired range of data points and the mode (AEPD or MEPD) to be used for end point determination.

If the auto-detection feature is enabled (set to Yes), then the instrument will proceed directly from data collection to AEPD without the usual intervening zoom window. Following AEPD, the results are displayed and the user can accept the results or reprocess the data using either AEPD or MEPD.

5.2.3 Parameters Used in the Calculation of the Analyte Concentration

After the end point has been determined, the AutoCAT 9000 automatically calculates the corresponding analyte concentration. The titrant concentration, sample volume, and dilution factors are used to calculate the analyte concentration, regardless of the method. In addition, the back titration method uses the concentration and volume of the reductant solution used to fix the sample. Each parameter must be properly set prior to running an analysis.

A Number of Decimals parameter is available in supervisor-level mode to set the number of decimal places used to report the analysis. For example, if Number of decimals is set to “4”, the experimental results will be reported as 0.3296 mg/L. If it is set to “2”, the result would be displayed as 0.33 mg/L.

5.2.3.1 Titrant Concentration

The titrant concentration (mN) can be entered manually or determined experimentally using the appropriate embedded titrant calibration routine. The exact concentration of the titrant is needed when entering the titrant concentration. See Obtaining the Certificate of Analysis for Hach Reagents on page 41.

5.2.3.2 Sample Volume

The sample volume (mL) is the volume of the sample solution actually placed on the instrument. This is a run-time parameter, allowing it to be changed each time a sample analysis is performed. The default sample volume is 200 mL. If the sample volume is changed, the new value is used as a default until the method defaults are reset or the value changed again.

Collecting and Accessing Data

50081_AutomatedTitration.fm Page 45

Collecting and Accessing Data

5.2.3.3 Dilution

If a sample solution is diluted prior to analysis, the sample parameter Dilution should be enabled (set to Yes), allowing access to three other parameters (Predilution vol., Final dilution vol., and Sample vol.). These parameters allow the calculated analyte concentration to be corrected for dilution and are only applicable when dilution is enabled.

This is generally done to bring the analyte concentration into the proper range for analysis. The AutoCAT 9000 can automatically correct any measured analyte concentration for sample dilution and three parameters are used to calculate analyte concentration:

• Predilution volume is the volume of the original sample

• Final dilution vol. is the volume of the sample after dilution

• Volume for Test is the volume of solution taken from the diluted sample

and analyzed.

Normally, AutoCAT returns the concentration of the sample actually presented to it (i.e., the concentration of the sample placed in the analysis beaker and analyzed by the instrument). Using the dilution information, the AutoCAT can automatically convert the concentration measured for the diluted sample into the concentration of the undiluted sample.

5.2.3.4 Reductant Concentration

When performing a back titration the sample is fixed by spiking it with reductant (either PAO or sodium thiosulfate) solution. Reductant concentration is the concentration (mN) of the solution used to fix the sample. The exact concentration of a Hach reductant solution can be obtained. See Obtaining the Certificate of Analysis for Hach Reagents on page 41.

5.2.3.5 Reductant Volume

In a back titration the sample is fixed by spiking it with reductant (either PAO or sodium thiosulfate) solution. Reductant Volume is the volume (mL) of the reductant solution used to fix the sample.

5.2.4 Analysis Calculations

When two or more consecutive new tests (as opposed to new samples) are run, the AutoCAT 9000 automatically calculates the mean and the standard deviation of the mean for the results obtained from the individual tests. This is equivalent to making several replicate measurements starting with identical samples for each measurement. The standard deviation of the mean is different than the standard deviation of the replicate measurements.

Collecting and Accessing Data Page 46

50081_AutomatedTitration.fm

Collecting and Accessing Data

5.2.4.1 Calculation of Mean

The mean is calculated using the following equation:

∑

Mean

Where:

Ri is the result from the ith replicate measurement (i.e., Test)

N is the number of replicate measurements.

5.2.4.2 Calculation of Standard Deviation (<5 replicate analyses)

When the number of replicate measurements is between 2 and 5, the standard deviation of the mean, S

i1=

-----------------=

is estimated using the following formula:

Mean

–

maxRmin

⎛⎞

---------------------------------

⎝⎠

------------------------------------------=

Where:

is the maximum value obtained from the replicate measurements

max

is the minimum value obtained from the replicate measurements

min

Q is taken from the following table:

N Q

21.128

31.693

42.059

52.326

5.2.4.3 Calculation of Standard Deviation (>5 replicate analyses)

If more than five replicate measurements (i.e., Tests) are made, the standard deviation of the mean, S

Mean

is calculated using the following formula:

Mean

∑

i1=

-------------------

i1=

--------------------------------------------=

∑

–

N1–()N

The final average is reported as: Mean (± S

Mean

)

Collecting and Accessing Data

50081_AutomatedTitration.fm Page 47

Collecting and Accessing Data

5.2.5 Retrieving Analysis Results from Archives

As part of the Good Laboratory Practices (GLP) capability incorporated into the AutoCAT 9000, all analysis results are automatically stored in the archive and organized according to method. For example, all results obtained using the free chlorine method are listed together. Before a particular result can be viewed the associated method must first be selected. The most recent result is always assigned to position “1” in the archive.

For example, if the user performs a series of 10 separate chlorine analyses, then the results for the most recent analysis will be stored in position “1” of the archive while the results of the least-recent analysis will be stored in position “10” of the archive. Each time a new analysis is performed, the results are pushed to the next (higher number) position in the archive. The AutoCAT 9000 can archive the results from 200 individual analyses; if more than 200 results are archived, the oldest analysis result is displaced in favor of the most recent result.

Important Note: All archived results are deleted when the system defaults are reset.

Collecting and Accessing Data Page 48

50081_AutomatedTitration.fm

Section 6 Calibration Procedures

Calibration Procedures

50081_CalibrationStopper.fm Page 49

Page 50 50081_CalibrationStopper.fm

PAO/5.64 mN

Amperometric Forward Titrant Calibration

Titration Workstation

Scope and Application: The following sequence guides the user through the calibration procedure for the

0.00564 N (5.64 mN) Phenylarsine Oxide titrants.

Sample Tips and Techniques

• Sample glassware must be cleaned and pretreated to satisfy any chlorine demand. See Section 7.2 Container Pretreatment on page 63 for additional information.

• Always use organic-free reagent water for sample dilution (Cat. No. 26415-49).

• Rinse the electrode, temperature probe, and anti-diffusion tip with deionized water before every titration.

Reagent Tips and Techniques

• Hach buffer reagents for chlorine titrations are highly recommended for this analysis.

• Download the “Certificate of Analysis” (COA) to obtain the exact concentration of any unopened bottle of Hach titrant or standard solution. See Obtaining the Certificate of Analysis for Hach Reagents on page 41.

• Never substitute buffers designed for calibrating pH meters. They may contain dyes that interfere with amperometric titration.

• Never use buffers contaminated with mold or bacteria.

• It is recommended that titrations for titrant calibration be performed in triplicate.

Instrument Tips and Techniques

• Adjust the contrast of the display by accessing the Methods menu, and then pressing 7 to lighten or 0 to darken.

• A distinction is drawn between running a new test and a new sample. Each test is a replicate run of the current or previous sample analysis. The AutoCAT automatically tracks the results of a series of tests, and automatically calculates the mean and standard deviation for all the results. Each test is given a different number, all of which are listed under the same Sample ID. When starting a new sample, a new ID is assigned.

• The AutoCAT can accommodate any sample size. Standard Methods recommends a default volume of 200 mL. The volume can be adjusted to expand the test range.

• The AutoCAT calculates concentration based on the sample volume. Make sure that the sample volume is correct.

• Rinse the electrode, temperature probe, and anti-diffusion tip with deionized water between calibrations.

• The data for any individual sample calibration may be repeatedly analyzed in manual or automatic mode. The results are not stored in the archives until they are accepted.

• Press the STOP key any time to interrupt instrument operation. The user will be given the option to resume, restart, or quit completely.

• Press CHECK MARK

• Press the DEL key during any timer period (except the Start Timer) to immediately exit the timer and proceed to the next step in the procedure.

• Flush the burette each day before the first sample test or calibration is performed. See Daily Start-up on page 26.

• Flush the burette when changing titrants. See Changing Titrants on page 25.

50081_PAONaThioCalibration.fm Page 51

key any time during data acquisition to halt data collection.

PAO/5.64 mN

AutoCAT Calibration Method PAO/5.64 mN Titrant

1. Turn the instrument on

if necessary and access the Titrants menu.

Press

4 to select Titrant

Library.

Note: Supervisor-mode is required to access calibrations. See Accessing Supervisor Mode on page 33.

5. Press the CHECK MARK

to change the titrant concentration input mode.

2. Highlight ID.

Press the to change.

CHECK MARK

6. Highlight Calibrate.

Press the to validate.

CHECK MARK

3. Highlight

PAO 5.64mN.

Press the

CHECK MARK

to validate.

Note: PAO 5.64mN has been chosen for demonstration purposes only.

7. The titrant

concentration input mode is now set to Calibrate and calibration parameters are available by scrolling this screen. Press return to the Titrants menu.

ESC twice to

4. Press 1 to select

Edit titrant.

8. Press 1 to select

Calibrate/Enter titrant conc.

Note: Titrant calibration is required before further analyses may be run, as indicated by the “Stormy” icon.

PAO/5.64 mN Page 52

50081_PAONaThioCalibration.fm

PAO/5.64 mN

9. Press 1 to select.

Run calibration to start the calibration sequence.

Note: Last Calibration will indicate the date of the previous calibration.

10. Press the CHECK MARK

to change the User or press to confirm.

Note: The user ID will be stored in the GLP archives for any future reference to this calibration.

Note: This screen will be skipped If User ID is disabled. See Section 3.3.2 Setting a User ID on page 27.

11. Highlight

Concentration.

Press the change the concentration or proceed to step 12.

Note: Use a recent lot of

0.0282 N Iodine Standard Solution for calibration.

Note: The default concentration may be changed to reflect standardization or the “Certificate of Analysis” value for a new bottle of titrant.

CHECK MARK to

12. Highlight Lot No.

Press the change the titrant lot number or proceed to step 13.

CHECK MARK to

13. Highlight Volume for

Test

Press the change the calibration volume or proceed to step 14.

Note: The default volume for the standard solution has been optimized for this embedded calibration.

CHECK MARK to

14. Prepare a calibration

sample.

a. Add 200 mL of DI-water

to a 250-mL glass beaker.

b. Using a Class A pipet, add

0.50 mL of recently standardized iodine solution.

c. Add 1 SwifTest

dispensation (0.1 g) of potassium iodide (KI), and

15. Rinse the electrode,

temperature probe, and anti-diffusion tip with deionized water.

Insert the specified magnetic stir bar into the calibration sample and place it onto the stirrer platform.

Lower the electrode head onto the beaker rim.

1 to confirm.

Press

16. Press 1 to confirm the

displayed increment or press the change the Increment.

Note: The default volume increment has been optimized for this embedded calibration; it may be changed to suit specific needs.

CHECK MARK to

1.0 mL of pH 4 acetate buffer.

Press

1 to confirm.

PAO/5.64 mN

50081_PAONaThioCalibration.fm Page 53

PAO/5.64 mN

17. The calibration titration

starts by filling the burette with titrant and subsequently dispensing a

2.2-mL predose of PAO into

the calibration sample. This will bring the electrical signal into measurable range.

18. The Start Timer will

begin.

This allows the electrode to stabilize before data is collected.

Once the electrode has stabilized, the AutoCAT will begin data acquisition and plot the titration curve in real time.

19. The Zoom range

determination window will display the titration curve.

Use the navigation keys to select and move the cursor (vertical lines) to define the range of data points for analysis.

Note: Defining the range of data points eliminates undesirable portions of the titration curve.

Select type of end point determination.

Press the Automatic. Proceed to step 22 or press Manual and proceed to step 20.

CHECK MARK for

DEL for

20. Select two line

segments, one on each side of the titration end point, by positioning cursors at the beginning and end of each segment.

Press the confirm changes, press to return to the previous window.

CHECK MARK to

DEL

21. Press the CHECK MARK

to accept the analysis. Proceed to step 24.

DEL to return to the

Press previous window (Zoom range determination) to adjust the linear segments and reanalyze the data.

PAO/5.64 mN Page 54

22. The AutoCAT will run

the analysis based on the automatic selection of linear segments.

Note: This algorithm requires approximately 60 seconds to complete.

23. Press the CHECK MARK

to accept the analysis.

Press DEL to return to the previous window (Zoom range determination) to adjust the linear segments and reanalyze the data.

24. Press 1 continue.

Press

2 to select More details

to view analysis statistics specific to the current calibration.

50081_PAONaThioCalibration.fm

PAO/5.64 mN

25. Press 1 to select

New Test and run a replicate calibration. Proceed to step 26.

Press

3 to select

End Analysis and store the titrant calibration value and return to the Methods menu.

Note: If subsequent replicate calibrations are run, the final titrant concentration will automatically be stored as the mean value from all the replicate titrant calibrations.

Safety

Summary of Method

26. The replicate analysis is

identical to the first calibration.

Upon completion of the analysis, and acceptance of the data, subsequent replicate analyses can be performed if desired.

1 to continue.

Press

2 to select

27. The mean and standard

deviation are calculated from the replicate analyses.

Press the accept the calibration value and return to the Titrants menu.

CHECK MARK to

In the Titrants menu, the accepted calibration has caused the Titrant tab icon to become sunny. This indicates that the titrant concentration has been properly calibrated and analyses may resume.

More Details to view analysis statistics specific to the current calibration.

Use good safety practices and laboratory techniques throughout the procedure. Consult the Material Safety Data Sheet (MSDS) for specific reagent(s) information.

The 0.00564 N reductant titrants, phenylarsine oxide (PAO) and sodium thiosulfate (NaThio), are standardized by titrating them against a know volume of 0.0282 N Iodine Standard Solution. The PAO/NaThio calibration procedure embedded in the AutoCAT 9000 is adapted from procedure 4500-Cl C. a. in “Standard Methods for Examination of Water and Wastewater“(20th Edition).

A calibration sample is prepared by adding 0.50 mL of 0.0282 N Iodine Standard Solution to 200 mL of chlorine-free deionized water. Potassium iodide (KI) and pH 4 acetate buffer are then added to the calibration sample. The calibration sample is then titrated using the desired reductant titrant. The embedded procedure calls for a 2.2-mL predose prior to titration. The titration end point is around 2.5 mL using the embedded method as defined. If the concentration of the Iodine Standard Solution is significantly less than 0.0282 N, it may be necessary to reduce the predose volume prior to titration. Titrate to an amperometric end point.

PAO/5.64 mN

50081_PAONaThioCalibration.fm Page 55

PAO/5.64 mN

Required Reagents

Description Qty. required per test Unit Cat. No.

Acetate Buffer Solution, pH 4, w/dropper................................................... 1 mL................. 100 mL ...............14909-32

Iodine Standard Solution, 0.0282 N ............................................................varies................ 1000 mL .............23333-53

Phenylarsine Oxide (PAO) Titrant, 0.00564 N

Potassium Iodide, SwifTest refill ................................................................0.10 g ............... 50 g.......................1077-60

Sodium Thiosulfate Standard Solution, stabilized, 0.00564 N

Required Apparatus

Beaker, Glass, 250-mL................................................................................1 ....................... each......................500-46H

Cylinder, Graduated, 250 mL......................................................................1 ....................... each.........................508-46

Magnetic Stir Bar, Teflon

®†

coated.............................................................1 ....................... each.....................50085-00

Pipet, Volumetric, Class A, 0.50 mL ...........................................................1 ....................... each.....................14515-34

SwifTest dispenser.......................................................................................1 ....................... each.....................28341-00

Optional Reagents

Dilution water, organic-free ........................................................................varies................ 500 mL ...............26415-49

Potassium Iodide, Powder Pillows ..............................................................1 ....................... 100/pkg.................1077-99

Optional Apparatus

Mini-printer, thermal, w/cable............................................................................................... each.....................A70P021

..........................................varies................ 1000 mL ...............1999-53

..................varies................ 1 L ......................24088-53

*Either titrant may be calibrated with this procedure. †Teflon is a Registered Trademark of EI DuPont Company.

FOR TECHNICAL ASSISTANCE, PRICE INFORMATION AND ORDERING:

In the U.S.A. – Outside the U.S.A. – On the Worldwide Web – ; E-mail –

Page 56 50081_PAONaThioCalibration.fm

Call 800-227-4224

toll-free

Contact the HACH office or distributor serving you.

www.hach.com techhelp@hach.com

HACH COMPANY

WORLD HEADQUARTERS Telephone: (970) 669-3050 FAX: (970) 669-2932

Iodine

Amperometric Back Titrant Calibration

Titration Workstation

Scope and Application: The following sequence guides the user through the calibration procedure for the

0.0282 N (28.2 mN) Iodine Standard Solution titrant.

Sample Tips and Techniques

• Sample glassware must be cleaned and pretreated to satisfy any chlorine demand. See Section 7.2 Container Pretreatment on

page 63 for additional information.

• Always use organic-free reagent water for sample dilution (Cat. No. 26415-49).

• Rinse the electrode, temperature probe, and anti-diffusion tip with deionized water before every calibration.

Reagent Tips and Techniques

• Download the “Certificate of Analysis” (COA) to obtain the exact concentration of any unopened bottle of Hach titrant or standard

solution. See Obtaining the Certificate of Analysis for Hach Reagents on page 41.

• Hach buffer reagents for chlorine titrations are highly recommended for this analysis.

• Never substitute buffers designed for calibrating pH meters. They may contain dyes that interfere with amperometric titration.

• Never use buffers contaminated with mold or bacteria.

• It is recommended that titrations for titrant calibration be performed in triplicate.

Instrument Tips and Techniques

• Adjust the contrast of the display by accessing the Methods menu and pressing 7

• A distinction is drawn between running a new test and a new sample on the AutoCAT. Each test is a replicate run of the current or

previous sample analysis. The AutoCAT automatically tracks the results of a series of tests, and automatically calculates the mean and standard deviation for all the results. Each test is given a different number, all of which are listed under the same Sample ID. When starting a new sample, a new ID is assigned.

• Rinse the electrode, temperature probe, and anti-diffusion tip with deionized water between calibrations.

• The AutoCAT 9000 can accommodate any sample size. Standard Methods recommends a default volume of 200 mL. The

volume can be adjusted to expand the test range.

• The AutoCAT 9000 calculates concentration based on the sample volume. Make sure that the sample volume is correct.

• The data for any sample calibration may be analyzed repeatedly in manual or automatic mode. The results are not stored in the

archives until they are accepted.

• Press the STOP key any time to interrupt instrument operation. The user will be given the option to resume, restart,

or quit.

to lighten, and 0 to darken.

• Press the CHECK MARK

• Press the DEL key during any timer period (except the Start Timer) to immediately exit the timer and proceed to the next step in

the procedure.

• Flush the burette each day before the first sample test or calibration is performed. See Daily Start-up on page 26.

• Flush the burette when changing titrants. See Changing Titrants on page 25.

50081_IodineCalibration.fm Page 57

key any time during data acquisition to halt data collection.

Iodine

AutoCAT Calibration Method Iodine Titrant Calibration

1. Turn the instrument on

if necessary and access the Titrants menu.

Press

4 to select

Titrant Library.

Note: Supervisor-mode is required to access calibrations. See Accessing Supervisor Mode on page 33.

5. Press the CHECK MARK

to change the titrant concentration input mode.

2. Highlight ID.

Press the to change.

CHECK MARK

6. Highlight Calibrate.

Press the validate.

CHECK MARK to

3. Highlight Iodine

28.2mN.

Press the

CHECK MARK

to validate.

7. The titrant

concentration input mode is now set to calibrate and the calibration parameters are now available by scrolling this screen.

ESC twice to return to

Press the Titrants menu.

4. Press 1 to select

Edit Titrant.

8. Press 1 to select

Calibrate/Enter titrant conc.

Note: Titrant calibration is now required before analyses may be run as indicated by the “Stormy” icon.

Iodine Page 58

50081_IodineCalibration.fm

Iodine

9. Press 1 to select.Run

Calibration to start the embedded calibration sequence.

Note: Last Calibration will indicate the date of the previous calibration.

10. Press the CHECK MARK

to change the User.

Press

1 to confirm.

Note: The user ID will be stored in the GLP archives for future reference.

Note: This screen is skipped if User ID is disabled. See Section 3.3.2 Setting a User ID on page 27.

11. Highlight

Concentration.

Press the change the concentration or proceed to step 12.

Note: The default concentration may be changed to reflect standardization or the “Certificate of Analysis” value for a new bottle.

CHECK MARK to

12. Highlight Lot No.

Press the change the titrant lot number or proceed to step 13.

CHECK MARK to

13. Highlight Volume for

Test 1.

Press the change the calibration volume or proceed to step 14.

CHECK MARK to

14. Prepare a calibration

sample.

a. Add 200 mL of DI-water

to a 250-mL glass beaker.

b. Add 1.00 mL of Arsenite

Standard Solution.

c. Add 4 g of sodium

bicarbonate.

Press

1 to confirm.

15. Rinse the electrode,

temperature probe, and anti-diffusion tip with deionized water.

Insert the magnetic stir bar into the calibration sample and place it on the stirrer platform.

Lower the electrode head

16. Press 1 to confirm.

Press the change the increment.

CHECK MARK to

onto the beaker rim.

1 to confirm.

Press

Iodine

50081_IodineCalibration.fm Page 59

Iodine

17. The calibration titration

starts by filling the burette with titrant and subsequently dispensing a

3.4-mL predose of Iodine into the calibration sample. This will bring the electrical signal into measurable range.

18. The Start Timer will

begin to allow the electrode to stabilize before data is collected.

After the electrode has stabilized, the AutoCAT will begin data acquisition and plot the titration curve in real time.

19. The Zoom Range

Determination window will display the titration curve.

Select and move the vertical lines (cursor) to define the range of data points for analysis.

Note: Defining the range of data points eliminates undesirable portions of the titration curve.

Select type of end point determination:

Press the Automatic and proceed to step 22 or press Manual and proceed to step 20.

CHECK MARK for

DEL for

20. Select two line

segments, one on each side of the titration end point, by positioning the cursors at the beginning and end of each segment.

Press the confirm changes.

Press previous window.

CHECK MARK to

DEL to return to the

21. Press the CHECK MARK

to accept the analysis. Proceed to step 24.

DEL to return to the

Press previous window (Zoom range determination) to adjust the linear segments and reanalyze the data.

Iodine Page 60

22. The AutoCAT will run

the analysis based on the automatic selection of linear segments.

Note: This algorithm requires approximately 60 seconds to complete the analysis.

23. Press the CHECK MARK

to accept the analysis.

Press DEL to return to the previous window (Zoom range determination) to adjust the linear segments and reanalyze the data.

24. Press 1 to select

Continue.

Press 2 to select More Details and view analysis statistics specific to the current calibration.

50081_IodineCalibration.fm

Iodine

25. Press 1 to select New

Test to run a replicate calibration. Proceed to step 26 or select

Press

2 to select End

Analysis and store the titrant calibration value and return to the Methods menu.

Note: If subsequent replicate calibrations are run, the final titrant concentration will automatically be stored as the mean value from all the replicate titrant calibrations.

Safety

Summary of Method

26. The replicate analysis is

identical to the first calibration.

Upon completion of the analysis, and acceptance of the data, subsequent replicate analyses can be performed if desired.

1 to select Continue

Press

27. The arithmetic mean is

calculated from the replicate analyses.

Press the accept the calibration value and return to the Titrants menu.

CHECK MARK to

In the Titrants menu, the accepted calibration has caused the Titrant tab icon to become sunny. This indicates that the titrant concentration has been properly calibrated and analyses may resume.

and perform additional tests and/or samples, or press

2 to

select More Details to view analysis statistics for the current calibration.

Use good safety practices and laboratory techniques throughout the procedure. Consult the Material Safety Data Sheet (MSDS) for specific reagent(s) information.

The 0.0282 N Iodine solution is standardized by titrating it against 0.1000 N Arsenite Standard Solution. The Iodine calibration procedure embedded in the AutoCAT 9000 is adapted from procedure 4500-Cl C. g. in “Standard Methods for Examination of Water and Wastewater” (20th Edition).

A calibration sample is prepared by adding 1.00 mL of standard 0.1000 N Arsenite solution and 4.0 g sodium bicarbonate (NaHCO

) to 200 mL of chlorine free deionized

water. The calibration sample is then titrated against the Iodine titrant. The embedded procedure calls for a 3.4-mL predose prior to titration. The titration end point is around

3.5 mL using the embedded method as defined. Perform a back titration to an amperometric end point.

Iodine

50081_IodineCalibration.fm Page 61

Iodine

Required Reagents

Description Qty. required per test Unit Cat. No.

Arsenite Standard Solution, 0.1000 N.........................................................1.00 mL............ 100 mL ...............28435-42

Sodium Bicarbonate ....................................................................................4 g .................... 454 g.......................776-01

Iodine Standard Solution, 0.0282 N ............................................................varies................ 1000 mL .............23333-53

Required Apparatus

Beaker, Glass, 250-mL................................................................................1 ....................... each......................500-46H

Cylinder, Graduated, 250 mL......................................................................1 ....................... each.........................508-46

®*

Magnetic Stir Bar, Teflon

Pipet, Volumetric, Class A, 1.00 mL ...........................................................1 ....................... each.....................14515-35

Optional Reagents

Dilution water, organic-free ........................................................................varies................ 500 mL ...............26415-49

Optional Apparatus

Mini-printer, thermal, w/cable............................................................................................... each.....................A70P021

coated.............................................................1 ....................... each.....................50085-00

*Teflon is a Registered Trademark of EI DuPont Company.

FOR TECHNICAL ASSISTANCE, PRICE INFORMATION AND ORDERING:

In the U.S.A. – Outside the U.S.A. – On the Worldwide Web – ; E-mail –

Call 800-227-4224

toll-free

Contact the HACH office or distributor serving you.

www.hach.com techhelp@hach.com

HACH COMPANY

WORLD HEADQUARTERS Telephone: (970) 669-3050 FAX: (970) 669-2932

Page 62 50081_IodineCalibration.fm

Section 7 Sampling

7.1 Chlorine

A common source of error when testing water samples for chlorine is the failure to obtain a representative sample. Free chlorine is a strong oxidizing agent and is very unstable in natural waters. It reacts readily with certain inorganic compounds and oxidizes organic compounds more slowly. Various factors, including reactant concentrations, pH, temperature, salinity, and sunlight influence the decomposition of free chlorine in water. Monochloramine, on the other hand, is much more persistent in the environment. Typically, the decay rate of monochloramine is tenfold slower than the decay of free chlorine in natural waters

Ideally, samples should be analyzed for chlorine on site. Because the amperometric method is usually performed in the laboratory, the delay between sample collection and analysis should be minimized. If sampling from a tap, allow water to flow 4–5 minutes to ensure a representative sample.

7.2 Container Pretreatment

Avoid plastic sample containers with a high chlorine demand. Pretreat glass sample containers to remove any chlorine demand by soaking in a dilute bleach solution (1 mL commercial bleach solution to 1 liter of water) for at least one hour. After soaking, rinse thoroughly with deionized/distilled water. Rinse sample containers thoroughly with deionized/distilled water after use to reduce the need for pretreatment.

7.3 Handling

Use separate, dedicated sample containers that are labelled for free and total chlorine determinations. Do not use the same sample containers for free and total chlorine analysis. Store your labelled sample containers for later use.

Avoid excess agitation and exposure to sunlight when sampling. Allow several volumes of the container to overflow and cap the sample container to eliminate headspace above the sample.

7.4 Samples for Back Titration

If the back-titration method is used for total chlorine determinations, preserve the sample on site. Add 1.00 mL of 0.00564 N phenylarsine oxide (PAO) and 1.0 mL of pH 4 acetate buffer to a clean, dry glass container with at least 250 mL capacity (such as a BOD bottle). At the sampling site, measure 200 mL of sample and carefully transfer it to the sample container. Swirl to mix. Do not overflow the sample container with preservative in it. Headspace will remain above the sample.

The delay between sample fixing and analysis should be minimized (usually less than 1 hour) to prevent bacterial decomposition of excess PAO in the sample. It is important that the entire contents of the sample container be transferred to the beaker used in the titration. See 5.2.3.4 Reductant Concentration and Section 5.2.3.5 Reductant Volume on page 46.

* Water Chlorination: Environmental Impact and Health Effects, Vol. 4, Book 1: Chemistry and Water Treatment, page 33.

Sampling

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Page 64 50081_Sampling.fm

Section 8 Titration Procedures

Titration Procedures

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Page 66 50081_ProcedureStopper.fm

Chlorine Dioxide

Generator Yield

Amperometric Forward Titration

Titration Workstation

Chlorine Dioxide Chlorite Free Chlorine

100–5000 mg/L as Cl02 100–5000 mg/L as Cl0 100–2000 mg/L as Cl

Scope and Application: For yield calculation of a chlorine dioxide generator*

* Procedure equivalent to Standard Methods 4500-ClO2 E.

Sample Tips and Techniques

• Soak all glassware in a strong chlorine dioxide (ClO2) solution (300–500 mg/L) for at least 1 hour.

Rinse thoroughly with deionized water. Use the glassware for this method only.

• Chlorine dioxide and its by-products are volatile and can be easily lost from aqueous solution. Minimize air contact by collecting

the effluent sample into an amber glass bottle with minimum headspace.

• Minimize agitation when measuring sample volumes. Remove sample portions with a volumetric pipet. Always place the tip at the

bottom of the sample container.

• Always use organic-free water for effluent sample dilution (Cat. No. 26415-49).

• Rinse the electrode, temperature probe, and anti-diffusion tip with deionized water before every titration.

Reagent Tips and Techniques

–

• Download the “Certificate of Analysis” (COA) to obtain the exact concentration of any unopened bottle of Hach titrant or standard

solution. See Obtaining the Certificate of Analysis for Hach Reagents on page 41.

• Hach buffer reagents for chlorine titrations are highly recommended for this analysis.

• Never substitute buffers designed for calibrating pH meters. They may contain dyes that interfere with amperometric titration.

• Never use buffers contaminated with mold or bacteria.

Instrument Tips and Techniques

• Adjust the contrast of the display by accessing the Methods menu and pressing 7

• A distinction is drawn between running a new test and a new sample. Each test is a replicate run of the current or previous

sample analysis. The AutoCAT 9000 automatically tracks the results of a series of tests, and automatically calculates the mean and standard deviation for all the results. Each test is given a different number, all of which are listed under the same Sample ID. When starting a new sample, a new ID is assigned.

• The AutoCAT 9000 can accommodate any sample size. The default volume for this method is 5.0 mL and can be adjusted to

expand the test range.

• The AutoCAT 9000 calculates concentration based on the sample volume. Ensure that the sample volume is correct.

• Press STOP at any time to interrupt instrument operation; the user can resume, restart, or quit completely.

• Press the CHECK MARK at any time during data acquisition to halt data collection.

• Press DEL during any timer period (except Start Timer) to immediately exit the timer and proceed to the next step.

• Press ESC

during any titration/calibration data collection period or timer to access Edition mode. See Edition Mode on page 30.

to lighten or 0 to darken.

• Flush the burette each day before the first sample test or calibration is performed. See Daily Start-up on page 26.

• Flush the burette when changing titrants. See Changing Titrants on page 25.

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Chlorine Dioxide Generator Yield

AutoCAT Titration Method ClO2 Yield Titration 1

1. Turn the instrument on

and access the Methods menu.

Press

2 to choose

Select Method.

2. Highlight

ClO

Gen. Yield

Press the to validate.

CHECK MARK

3. Press 1 to select

Run method.

This method uses the 0.10 N Sodium Thiosulfate titrant. See Software Setup for Titrant Installation on page 38.

4. Measure 1–5 mL of

generator effluent sample with a pipet and transfer to a 250-mL beaker containing the magnetic bar.

Note: All containers must be pretreated for chlorine demand, see Container Pretreatment on page 63.

5. Dilute the sample to

approximately 200-mL with Organic Free water.

Chlorine Dioxide Generator Yield Page 68

6. Place the sample onto

the AutoCAT 9000 stirrer platform.

7. Verify User.

Press the enter a new user or press confirm.

Note: This screen will be skipped if the User ID is disabled. See Setting a User ID on page 27.

CHECK MARK to

1 to

8. Highlight Sample ID.

Press the enter a new sample ID or proceed to step 9.

50081_ChlorineDioxideGeneratorYield.fm

CHECK MARK to

Chlorine Dioxide Generator Yield

9. Highlight Predilution

volume.

Press the enter the volume pipetted in Step 4.

Press

Note: Final dilution volume and Volume for Test default values need not be changed.

CHECK MARK and

1 to confirm.

10. Add 1 dose of pH 7.0

Phosphate Buffer.

Press the to confirm.

Note: Phosphate buffer is added to adjust the sample pH. The precise amount added is not crucial for the accuracy or precision of the analysis.

CHECK MARK

11. Use the measuring

spoon to add 1.0 g of potassium iodide (KI).

Press the to confirm.

Note: KI is added in excess. The precise amount added is not crucial for the accuracy or precision of the analysis.

CHECK MARK

12. The timer will start,

allowing the reagents to mix before starting the titration.

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Chlorine Dioxide Generator Yield

13. Lower the electrode

head onto the beaker rim.

Press the to confirm.

CHECK MARK

14. The analysis parameters

that have been stored for the current Sub-ID may be edited at this time.

Highlight the appropriate line and press the

CHECK MARK to change one

of the analysis parameters or press 1 to confirm.

Note: Any changes made will become the new default parameters for this method Sub-ID.

Note: These Sub-ID parameters can be edited here as 'run-time' settings, or from the Main Menu as described in Section 3.5.

Note: This step will be skipped if auto-scaling software is enabled.

15. The Start Timer

will start to allow the electrode to stabilize before data collection.

Once the electrode has stabilized, the AutoCAT will begin data acquisition and plot the titration curve.

16. The Zoom Range

Determination window will display the titration curve.

Use the navigation buttons to select and move the cursors to define the range of data points for analysis.

Note: Defining the range of data points excludes undesirable portions of the titration curve from the analysis.

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Chlorine Dioxide Generator Yield

17. Select type of end point

determination.

Press

DEL for Manual.

Note: Automatic determination attempts to identify linear segments without user input and is not recommended for this method.

18. Use the navigation keys

to select two line segments, one on each side of the titration end point, by positioning vertical lines (cursors) at the beginning and end of each segment.

Press the confirm changes or press

DEL to return to the Zoom

window.

Note: For more information on manual EP determination, see page 135.

CHECK MARK to

19. Press the CHECK MARK

to accept the analysis and proceed to Titr. 2 or press

DEL to return to the previous

window to adjust the linear segments and reanalyze the data.

Note: The analysis data may be analyzed as many times as needed from the Zoom Range Determination window, in manual and/or automatic modes. The results are not stored until accepted.

Note: The AutoCAT 9000 stores all titration results and then automatically calculates each analyte value after the procedure is complete.

Chlorine Dioxide Generator Yield

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Chlorine Dioxide Generator Yield

AutoCAT Titration Method ClO2 Yield Tiration 2

1. Raise the electrode

head.

Add 2.0 mL of

2.5 N Hydrochloric acid and stir for several seconds.

Carefully remove the sample from the stirrer platform and place in the dark.

Press the to confirm.

CHECK MARK

2. The timer will start.

This timer allows a 5-minute reaction period before starting the titration.

3. Remove the sample

from the dark and carefully place onto the AutoCAT stirrer platform.

Lower the electrode head onto the beaker rim.

Press the to confirm.

CHECK MARK

4. The analysis parameters

that have been stored for the current Sub-ID may be edited at this time.

Highlight the appropriate line and press CHECK MARK to change one of the analysis parameters or press 1 to confirm.

Note: Any changes made will become the new default parameters for this method Sub-ID.

Note: These Sub-ID parameters can be edited here as 'run-time' settings, or from the Main Menu as described in Section 3.5.

Note: This step will be skipped if autoscaling software is enabled.

Chlorine Dioxide Generator Yield Page 72

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Chlorine Dioxide Generator Yield

5. The Start Timer will

begin, allowing the electrode to stabilize before data is collected.

Once the electrode has stabilized, the AutoCAT will begin data acquisition and plot the titration curve.

6. The Zoom Range

Determination window will display the titration curve.

Select and move the cursors to define the range of data points for analysis.

7. Select the type of end

point determination.

Press

DEL for Manual.

Note: Automatic determination attempts to identify linear segments without user input and is not recommended for this method.

8. Using the navigation

keys, select two line segments, one on each side of the titration end point, by positioning vertical lines (cursors) at the beginning and end of each segment.

Press the confirm changes.

Press Zoom window.

Note: For more information on manual EP determination, see page 135.

CHECK MARK to

DEL to return to the

9. Press the CHECK MARK

to accept the analysis and proceed to Titration 3 or press

DEL to return to the

previous window to adjust the linear segments and reanalyze the data.

Chlorine Dioxide Generator Yield

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Chlorine Dioxide Generator Yield

AutoCAT Titration Method ClO2 Yield Titration 3

1. Press the CHECK MARK

to enter a new volume.

Press

1 to confirm.

5. Purge nitrogen gas

through the sample for 15 minutes.

When the timer beeps, transfer the purged sample into a 250-mL beaker. Add the magnetic stir bar.

Note: If the nitrogen purge has already been performed, press DEL to skip this timer and proceed to the next step.

2. Transfer 200 mL of

organic-free DI water to a Gas Washing Bottle (GWB). Add identical volume of sample pipetted in Titration 1, Step 4.

Add 1 dose of pH 7.0 phosphate buffer, and swirl to mix.

6. Use the measuring

spoon to add 1.0 g of potassium iodide (KI).

Place the sample onto the stirrer platform.

Press the to confirm.

Note: KI is added in excess. The precise amount added is not crucial for the accuracy or precision of the analysis.

CHECK MARK

3. Insert the purge tube

and dispersion tip into the GWB. Connect the GWB inlet to a tank of purified nitrogen.

7. The timer will begin,

allowing the reagents to mix before starting the titration.

4. Use a needle valve

to adjust the flow of nitrogen to provide a steady stream of bubbles through the sample.

Press the

CHECK MARK

to continue.

8. Lower the electrode

head onto the beaker rim.

Press the to confirm.

CHECK MARK

Chlorine Dioxide Generator Yield Page 74

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Chlorine Dioxide Generator Yield

9. The analysis parameters

that have been stored for the current Sub-ID may be edited at this time.

Highlight the appropriate line and press the

CHECK MARK to change one

of the analysis parameters or press 1 to confirm.

Note: Any changes made will become the new default parameters for this method Sub-ID.

Note: These Sub-ID parameters can be edited here as 'run-time' settings, or from the Main Menu as described in Section 3.5.

Note: This step will be skipped if autoscaling software is enabled.

10. The Start Timer will

begin, allowing the electrode to stabilize before data is collected.

After the electrode has stabilized, the AutoCAT will begin data acquisition and plot the titration curve in real time.

11. The Zoom range

determination window will display the titration curve.

Select and move the cursors to define the range of data points for analysis.

Proceed to step 12.

12. Select type of end point

determination.

Press

DEL for Manual.

Note: Automatic determination attempts to identify linear segments without user input but is not recommended for this method.

Chlorine Dioxide Generator Yield

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Chlorine Dioxide Generator Yield

13. Use the navigation

buttons to select two line segments, one on each side of the titration end point, by positioning the cursors at the beginning and end of each segment (indicated by arrows).

Press the confirm changes or press

DEL to return to the previous

window.

Note: For more information on manual EP determination, see page 135.

CHECK MARK to

14. Press the CHECK MARK

to accept the analysis and proceed to Titration 4.

Press

DEL to return to the

previous window to adjust the linear segments and reanalyze the data.

Chlorine Dioxide Generator Yield Page 76

50081_ChlorineDioxideGeneratorYield.fm

Chlorine Dioxide Generator Yield

AutoCAT Titration Method ClO2 Yield Titration 4

1. Raise the electrode

head.

Add 2.0 mL of

2.5 N Hydrochloric acid and stir for several seconds.

Carefully remove the sample from the stirrer platform and place in the dark.

Press the to confirm.

CHECK MARK

2. The timer will start.

This timer allows a 5-minute reaction period before starting the titration.

3. Remove the sample

from the dark and place onto the AutoCAT titration platform.

Lower the electrode head onto the beaker rim.

Press the to confirm.

CHECK MARK

4. The analysis parameters

that have been stored for the current Sub-ID may be edited at this time.

Highlight the appropriate line and press the

CHECK MARK to change one

of the analysis parameters or press 1 to confirm.

Note: Any changes made will become the new default parameters for this method Sub-ID.

Note: These Sub-ID parameters can be edited here as 'run-time' settings, or from the Main Menu as described in Section 3.5.

Note: This step will be skipped if autoscaling software is enabled.

Chlorine Dioxide Generator Yield

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Chlorine Dioxide Generator Yield

5. The Start Timer will

begin, allowing the electrode to stabilize before data is collected.

Once the electrode has stabilized, the AutoCAT will begin data acquisition and plot the titration curve in real time.

6. The Zoom Range

Determination window will display the titration curve.

Select and move the cursors to define the range of data points for analysis.

Proceed to step 7.

7. Select type of end point

determination.

Press

DEL for Manual.

Note: Automatic determination attempts to identify linear segments without user input but is not recommended for this method.

8. Use the navigation

buttons to select two line segments, one on each side of the titration end point, by positioning the cursors at the beginning and end of each segment.

Press the confirm changes or press

DEL to return to the previous

window.

Note: For more information on manual EP determination, see page 135.

CHECK MARK to

9. Press the CHECK MARK

to accept the analysis.

Press

DEL to return to the

previous window. Adjust the linear segments and reanalyze the data.

10. The analysis for this test

is complete.

Use the the second page of results, or: Press and analyze additional samples, perform more tests, or finish analyses.

Press and view analysis statistics specific to the current sample ID.

Chlorine Dioxide Generator Yield Page 78

RIGHT key to view

1 to select Continue

2 to select More Details

11. View Yield and Ratio

on this screen, and then press the to main results screen.

LEFT key to return

12. Press 1 to select

New Test to run a replicate sample.

2 to select New Sample

Press to initiate analysis of a new sample with a new Sample ID. See Instrument Tips and Techniques on page 67.

Press

3 to select

End Analysis and return to the Methods menu.

50081_ChlorineDioxideGeneratorYield.fm

Summary of Method

Chlorine Dioxide Generator Yield

This method is used to determine the yield from a chlorine dioxide generator system and to optimize the generator performance. Yield is defined as the ratio of chlorine dioxide produced to the theoretical maximum. The percent yield is calculated as follows:

------------------------------------------------------------------------------------------------------------------------------

sum of the total chlor-oxy species concentration

Most modern generators will have yields of 95% or better.

The AutoCAT gives results for chlorine dioxide (ClO chlorine (Cl

). Four successive titrations are required:

chlorine dioxide concentration

Titration 1 Cl

+→

), chlorite (ClO

---

ClO

100× % yield=

–

), and free

+→

ClO

–

→

---

ClO

Titration 2

Titration 3 Cl

Titration 4 ClO

(not volatilized by a nitrogen gas purge)→

–

The AutoCAT 9000 stores all titration results and, after completion, calculates each analyte value.

This method can be greatly accelerated by purging a sample portion (used for Titrations 3 and 4) with nitrogen while performing Titrations 1 and 2.

Another measurement used to gauge ClO

generator production is the ratio of Titration 2

to Titration 1 results. This provides an estimate of any untreated chlorite or chlorine feedstock in the generator effluent. This method is only applicable to those generators using chlorite and gaseous chlorine feeds. Ideally, the optimum ratio of Titration 2/Titration 1 results should lie between 3.9 and 4.05. See Tab l e 1.

Table 1 Generator Effluent Condition

Titr 2/Titr 1 Ratio Effluent Condition

Less than 3.9 Unreacted chlorine, possible chlorate contamination

3.9–4.05 Optimum

Greater than 4.05 Unreacted chlorite

Typically, a ratio of less than 3.75 indicates a generator yield of less than 95%.

Chlorine Dioxide Generator Yield

50081_ChlorineDioxideGeneratorYield.fm Page 79

Chlorine Dioxide Generator Yield

Required Reagents

Description Qty. required per test Unit Cat. No.

Hydrochloric Acid Standard Solution, 2.5 N ..............................................4 mL................. 100 mL .................1418-32

Phosphate Buffer pH 7, w/dropper..............................................................2 mL................. 100 mL ...............21553-32

Potassium Iodide, ACS................................................................................1.0 g ................. 100 g....................167-26H

Sodium Thiosulfate Solution, 0.10 N.......................................................... varies................ 1000 mL .................323-53

Required Apparatus

Description Qty. required per test Unit Cat. No.

Beaker, Glass, 250-mL................................................................................1 ....................... each......................500-46H

Gas Washing Bottle .....................................................................................1....................... each.....................26622-00

®*

Magnetic Stir Bar, Teflon

Measuring Spoon, 1.0-g (NaCl weight), molded plastic.............................1 ....................... each.........................510-00

Pipet, Volumetric, Class A, 5.00-mL...........................................................1 ....................... each.....................14515-37

Support, Ring Stand.....................................................................................1 ....................... each.........................563-00

Support Ring, for GWB...............................................................................1 ....................... each.....................26563-00

Optional Reagents

Dilution water, organic-free ........................................................................varies................ 500 mL ...............26415-49

Optional Apparatus

Cylinder, Graduated, 250 mL......................................................................1 ....................... each.........................508-46

Mini-printer, thermal, w/cable............................................................................................... each.....................A70P021

Pipet, Volumetric, Class A, 1.00 mL ...........................................................1 ....................... each.....................14515-35

Pipet, Volumetric, Class A, 2.00 mL ...........................................................1 ....................... each.....................14515-36

Pipet, Volumetric, Class A, 3.00 mL ...........................................................1 ....................... each.....................14515-03

Pipet, Volumetric, Class A, 4.00 mL ...........................................................1 ....................... each.....................14515-04

coated.............................................................1 ....................... each.....................50085-00

*Teflon is a Registered Trademark of EI DuPont Company.

FOR TECHNICAL ASSISTANCE, PRICE INFORMATION AND ORDERING:

In the U.S.A. – Outside the U.S.A. – On the Worldwide Web – ; E-mail –

Page 80 50081_ChlorineDioxideGeneratorYield.fm

Call 800-227-4224

toll-free

Contact the HACH office or distributor serving you.

www.hach.com techhelp@hach.com

HACH COMPANY

WORLD HEADQUARTERS Telephone: (970) 669-3050 FAX: (970) 669-2932

Chlorine Dioxide

w/ Chlorite and Free Chlorine

Amperometric Forward Titration

Titration Workstation

Chlorine Dioxide Chlorite Free Chlorine

0.10–5.00 mg/L as Cl0

0.10–2.00 mg/L as Cl

–

Scope and Application: For water and wastewater**

* Higher ranges can be determined through sample dilution. See Section 5.2.3.3 Dilution on page 46. **Procedure equivalent to Standard Methods 4500-ClO

Sample Tips and Techniques

• Soak all glassware in a strong chlorine dioxide (ClO2) solution (300–500 mg/L) for at least 1 hour.

Rinse thoroughly with deionized water. Use the glassware for this method only.

• Chlorine dioxide and its by-products are volatile and can be easily lost from aqueous solution. Minimize air contact by attaching a

flexible hose to a tap and placing the end at the bottom of a 1-L amber glass bottle. Turn on the tap and allow several volumes to overflow, then slowly remove the sample line and cap the container with minimum headspace.

• Minimize agitation when measuring sample volumes. Remove sample portions with a volumetric pipet. Always place the tip at the

bottom of the sample container. If using 200-mL sample increments, use a 100-mL pipet to withdraw two portions of sample.

• Always use organic-free water for sample dilution (Cat. No. 26415-49).

• Rinse the electrode, temperature probe, and anti-diffusion tip with deionized water before every titration.

Reagent Tips and Techniques

• Download the “Certificate of Analysis” (COA) to obtain the exact concentration of any unopened bottle of Hach titrant or standard

solution. See Obtaining the Certificate of Analysis for Hach Reagents on page 41.

• Hach buffer reagents for chlorine titrations are highly recommended for this analysis.

• Never substitute buffers designed for calibrating pH meters. They may contain dyes that interfere with amperometric titration.

• Never use buffers contaminated with mold or bacteria.

Instrument Tips and Techniques

• Adjust the contrast of the display by accessing the Methods menu and pressing 7

• A distinction is drawn between running a new test and a new sample. Each test is a replicate run of the current or previous

• The AutoCAT 9000 can accommodate any sample size. Standard Methods recommends a default volume of 200 mL. The

volume can be adjusted to expand the test range.

• The AutoCAT 9000 calculates concentration based on the sample volume. Make sure that the sample volume is correct.

• Press STOP any time to interrupt instrument operation; the user can resume, restart, or quit completely.

• Press the CHECK MARK any time during data acquisition to halt data collection.

• Press DEL during any timer period (except Start Timer) to immediately exit the timer and proceed to the next step.

• Press ESC

• Flush the burette each day before the first sample test or calibration is performed. See Daily Start-up on page 26.

during any titration/calibration data collection period or timer to access Edition mode. See Edition Mode on page 30.

to lighten or 0 to darken.

• Flush the burette when changing titrants. See Changing Titrants on page 25.

Chlorine Dioxide

50081_Chlorine_ChlorineDioxide.fm Page 81

Chlorine Dioxide

AutoCAT Titration Method Chlorine Dioxide Titr. 1

1. Turn the instrument on

if necessary and access the Methods menu.

Press

2 to choose

Select Method.

5. Place the sample onto

the AutoCAT 9000 stirrer platform.

2. Highlight

Chlorine dioxide.

Press the

CHECK MARK

to validate.

6. Verify User.

Press the enter a new user or press confirm.

Note: This screen will be skipped if the User ID is disabled. See Setting a User ID on page 27.

CHECK MARK to

1 to

3. Press 1 to select

Run method.

This method used the

5.64mN PAO titrant. See

Software Setup for Titrant Installation on page 38.

7. Highlight Sample ID.

Press the enter a new sample ID or proceed to step 8.

CHECK MARK to

4. Measure 200 mL of

sample solution with a pipet and transfer to a 250-mL beaker with the specified magnetic stir bar.

All containers must be pretreated for chlorine demand, see Container Pretreatment on page 63.

8. Highlight Volume for

Test 1.

Press the enter a new volume.

Press

CHECK MARK to

1 to confirm.

Chlorine Dioxide Page 82

50081_Chlorine_ChlorineDioxide.fm

Chlorine Dioxide

9. Add 1.0 mL of pH 7.0

Phosphate Buffer Solution.

Press the

CHECK MARK

to confirm.

Note: Phosphate buffer is added to adjust the sample pH. The precise amount added is not crucial for the accuracy or precision of the analysis.

13. The analysis parameters

that have been stored for the current Sub-ID may be edited at this time.

Highlight the appropriate line and press the

CHECK MARK to change one

of the analysis parameters or

1 to confirm.

press

Note: Any changes made will become the new default parameters for this method Sub-ID.

Note: These Sub-ID parameters can be edited here as 'run-time' settings, or from the Main Menu as described in Section 3.5.

Note: This step will be skipped if auto-scaling software is enabled.

10. Use the measuring

spoon to add 1.0 g of potassium iodide (KI).

Press the

CHECK MARK

to confirm.

Note: KI is added in excess. The precise amount added is not crucial for the accuracy or precision of the analysis.

14. The Start Timer

will start to allow the electrode to stabilize before data collection.

Once the electrode has stabilized, the AutoCAT will begin data acquisition and plot the titration curve.

11. The timer will start.

This allows a short period of time for the reagents to mix before starting the titration.

15. The Zoom Range

Determination window will display the titration curve.

Use the navigation buttons to select and move the cursors to define the range of data points for analysis.

Note: Defining the range of data points excludes undesirable portions of the titration curve from the analysis.

12. Lower the electrode

head onto the beaker rim.

Press the

CHECK MARK

to confirm.

16. Select type of end point

determination.

Press

DEL for Manual.

Note: Automatic determination attempts to identify linear segments without user input and is not recommended for this method.

Chlorine Dioxide

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Chlorine Dioxide

17. Use the navigation keys

to select two line segments, one on each side of the titration end point, by positioning vertical lines (cursors) at the beginning and end of each segment. Press the confirm changes or press

DEL to return to the Zoom

window.

Note: For more information on manual EP determination, see page 135.

CHECK MARK to

18. Press the CHECK MARK

to accept the analysis and proceed to Titr. 2 or press

DEL to return to the previous

window to adjust the linear segments and reanalyze the data.

Note: The analysis data may be analyzed as many times as needed from the Zoom Range Determination window, in manual and/or automatic modes. The results are not stored until accepted.

Note: The AutoCAT 9000 stores all titration results and then automatically calculates each analyte value after the procedure is complete.

Chlorine Dioxide Page 84

50081_Chlorine_ChlorineDioxide.fm

Chlorine Dioxide

AutoCAT Titration Method Chlorine Dioxide Titr. 2

1. Raise the electrode

head.

Add 2.0 mL of

2.5 N Hydrochloric acid and stir for several seconds.

Carefully remove the sample from the stirrer platform and place in the dark.

Press the to confirm.

CHECK MARK

2. The timer will start.

This timer allows a 5-minute reaction period before starting the titration.

3. Remove the sample

from the dark and carefully place onto the AutoCAT stirrer platform.

Lower the electrode head onto the beaker rim.

Press the to confirm.

CHECK MARK

4. The analysis parameters

that have been stored for the current Sub-ID may be edited at this time.

Highlight the appropriate line and press the

CHECK MARK to change one

of the analysis parameters or press 1 to confirm.

Note: Any changes made will become the new default parameters for this method Sub-ID.

Note: These Sub-ID parameters can be edited here as 'run-time' settings, or from the Main Menu as described in Section 3.5.

Note: This step will be skipped if autoscaling software is enabled.

Chlorine Dioxide

50081_Chlorine_ChlorineDioxide.fm Page 85

Chlorine Dioxide

5. The Start Timer will

begin to allow the electrode to stabilize before data is collected.

Once the electrode has stabilized, the AutoCAT will begin data acquisition and plot the titration curve.

6. The Zoom Range

Determination window will display the titration curve.

Note: Select and move the

cursors to define the range of data points for analysis.

7. Select the type of end

point determination.

Press

DEL for Manual.

Automatic determination attempts to identify linear segments without user input and is not recommended for this method.

8. Using the navigation

keys, select two line segments, one on each side of the titration end point, by positioning vertical lines (cursors) at the beginning and end of each segment.

Press the confirm changes.

Press Zoom window.

Note: For more information on manual EP determination, see page 135.

CHECK MARK to

DEL to return to the

9. Press the CHECK MARK

to accept the analysis and proceed to Titr. 3 or press

DEL to return to the previous

window to adjust the linear segments and reanalyze the data.

Note: For more information on manual EP determination, see page 135.

Chlorine Dioxide Page 86

50081_Chlorine_ChlorineDioxide.fm

Chlorine Dioxide

AutoCAT Titration Method Chlorine Dioxide Titr. 3

1. Press the CHECK MARK

to enter a new volume.

Press

1 to confirm.

5. Purge nitrogen gas

through the sample for 15 minutes.

When the timer beeps, transfer the purged sample into a 250-mL beaker. Add the specified magnetic stir bar.

Note: If the nitrogen purge has already been performed, press DEL to skip this timer and proceed to the next step.

2. Pipet 200 mL sample

into a Gas Washing Bottle (GWB).

Add 1 mL of pH 7 Phosphate buffer.

Swirl to mix.

6. Use the measuring

spoon to add 1.0 g of potassium iodide (KI).

Place the sample onto the stirrer platform.

Press the to confirm.

Note: KI is added in excess. The precise amount added is not crucial for the accuracy or precision of the analysis.

CHECK MARK

3. Insert the purge tube

and dispersion tip into the GWB. Connect the GWB inlet to a tank of purified nitrogen.

7. The timer will start to

allow a short period of time for the reagents to mix before starting the titration.

4. Use a needle valve

to adjust the flow of nitrogen to provide a steady stream of bubbles through the sample.

Press the

CHECK MARK

to continue.

8. Lower the electrode

head onto the beaker rim.

Press the to confirm.

CHECK MARK

Chlorine Dioxide

50081_Chlorine_ChlorineDioxide.fm Page 87

Chlorine Dioxide

9. The analysis parameters

that have been stored for the current Sub-ID may be edited at this time.

Highlight the appropriate line and press the

CHECK MARK to change one

of the analysis parameters or press 1 to confirm.

Note: Any changes made will become the new default parameters for this method Sub-ID.

Note: These Sub-ID parameters can be edited here as 'run-time' settings, or from the Main Menu as described in Section 3.5.

Note: This step will be skipped if autoscaling software is enabled.

10. The Start Timer will

begin to allow the electrode to stabilize before data is collected.

After the electrode has stabilized, the AutoCAT will begin data acquisition and plot the titration curve in real time.

11. The Zoom range

determination window will display the titration curve.

Select and move the cursors to define the range of data points for analysis.

Proceed to step 12.

12. Select type of end point

determination.

Press

DEL for Manual.

Note: Automatic determination attempts to identify linear segments without user input but is not recommended for this method.

Chlorine Dioxide Page 88

50081_Chlorine_ChlorineDioxide.fm

Chlorine Dioxide

13. Use the navigation

buttons to select two line segments, one on each side of the titration end point, by positioning the cursors at the beginning and end of each segment (indicated by arrows).

Press the confirm changes or press

DEL to return to the previous

window.

Note: For more information on manual EP determination, see page 135.

CHECK MARK to

14. Press the CHECK MARK

to accept the analysis and proceed to Titr. 4.

Press

DEL to return to the

previous window to adjust the linear segments and reanalyze the data.

Note: For more information on manual EP determination, see page 135.

Chlorine Dioxide

50081_Chlorine_ChlorineDioxide.fm Page 89

AutoCAT Titration Method Chlorine Dioxide Titr. 4

1. Raise the electrode

head.

Add 2.0 mL of

2.5 N Hydrochloric acid and stir for several seconds.

Carefully remove the sample from the stirrer platform and place in the dark.

Press the to confirm.

CHECK MARK

2. The timer will start.

This timer allows a 5-minute reaction period before starting the titration.

3. Remove the sample

from the dark and place onto the AutoCAT titration platform.

Lower the electrode head onto the beaker rim.

Press the to confirm.

CHECK MARK

4. The analysis parameters

that have been stored for the current Sub-ID may be edited at this time.

Highlight the appropriate line and press the

CHECK MARK to change one

of the analysis parameters or press 1 to confirm.

Note: Any changes made will become the new default parameters for this method Sub-ID.

Note: These Sub-ID parameters can be edited here as 'run-time' settings, or from the Main Menu as described in Section 3.5.

Note: This step will be skipped if autoscaling software is enabled.

Chlorine Dioxide

5. The Start Timer will

begin.

This allows the electrode to stabilize before data is collected.

Once the electrode has stabilized, the AutoCAT 9000 will begin data acquisition and plot the titration curve in real time.

6. The Zoom Range

Determination window will display the titration curve.

Select and move the cursors to define the range of data points for analysis.

Proceed to step 7.

7. Select type of end point

determination.

Press

DEL for Manual.

Note: Automatic determination attempts to identify linear segments without user input but is not recommended for this method.

8. Use the navigation

buttons to select two line segments, one on each side of the titration end point, by positioning the cursors at the beginning and end of each segment.

Press the confirm changes or press

DEL to return to the previous

window.

Note: For more information on manual EP determination, see page 135.

CHECK MARK to

9. Press the CHECK MARK

to accept the analysis.

Press DEL to return to the previous window. Adjust the linear segments and reanalyze the data.

10. The analysis for this test

is complete.

Press 1 to select Continue to perform additional tests and/or samples, or to finish analyses.

2 to select More Details

Press to view analysis statistics specific to the current sample ID.

11. Press 1 to select

New Test to run a replicate sample.

2 to select New Sample

Press to initiate analysis of a new sample with a new Sample ID. See Instrument Tips and

Techniques on page 81.

Press

3 to select

End Analysis to return to the Methods menu.

Chlorine Dioxide

50081_Chlorine_ChlorineDioxide.fm Page 91

Chlorine Dioxide

)

Summary of Method

This procedure permits the determination of chlorine dioxide (ClO2), chlorite (ClO and chlorine (Cl

) in the sample.

–

This is a multi-step procedure involving four amperometric titrations and two titration samples. These titrations are as follows:

Sample 1

Titration 1 Cl

-- -

+→

ClO

Titration 2

-- -

ClO

+→

ClO

–

Sample 2

Titration 3 Cl

Titration 4 ClO

→

(not volatized by a nitrogen gas purge

→

–

The AutoCAT 9000 stores all titration results and, after completion, calculates each analyte value.

This method can be greatly accelerated by purging a sample portion (used for Titrations 3 and 4) with nitrogen while performing titrations 1 and 2.

Required Reagents

Description Qty. required per test Unit Cat. No.

Phenylarsine Oxide (PAO) Titrant, 0.00564 N............................................ varies................ 1000 mL ...............1999-53

Hydrochloric Acid Standard Solution, 2.5 N ..............................................4 mL................. 100 mL .................1418-32

Phosphate Buffer pH 7, w/dropper..............................................................2 mL................. 100 mL ...............21553-32

Potassium Iodide, ACS................................................................................2.0 g ................. 100 g....................167-26H

Required Apparatus

Description Qty. required per test Unit Cat. No.

Beaker, Glass, 250-mL................................................................................1 ....................... each......................500-46H

Gas Washing Bottle .....................................................................................1....................... each.....................26622-00

Magnetic Stir Bar, Teflon

Measuring Spoon, 1.0-g (NaCl weight), molded plastic.............................1 ....................... each.........................510-00

Pipet, Volumetric, Class A, 100-mL............................................................1 ....................... each.....................14515-42

Support, Ring Stand.....................................................................................1 ....................... each.........................563-00

Support Ring, for GWB...............................................................................1 ....................... each.....................26563-00

®*

coated.............................................................1 ....................... each.....................50085-00

Optional Reagents

Dilution water, organic-free ........................................................................varies................ 500 mL ...............26415-49

Optional Apparatus

Mini-printer, thermal, w/cable............................................................................................... each.....................A70P021

Cylinder, Graduated, 250 mL......................................................................1 ....................... each.........................508-46

*Teflon is a Registered Trademark of EI DuPont Company.

FOR TECHNICAL ASSISTANCE, PRICE INFORMATION AND ORDERING:

In the U.S.A. – Outside the U.S.A. – On the Worldwide Web – ; E-mail –

Page 92 50081_Chlorine_ChlorineDioxide.fm

Call 800-227-4224

toll-free

Contact the HACH office or distributor serving you.

www.hach.com techhelp@hach.com

HACH COMPANY

WORLD HEADQUARTERS Telephone: (970) 669-3050 FAX: (970) 669-2932

Free Chlorinec

Amperometric Forward Titration

Titration Workstation

0.100–5.000 mg/L as Cl2*

Scope and Application: For drinking water; USEPA accepted for reporting**

* Higher ranges can be determined through sample dilution. See Section 5.2.3.3 Dilution on page 46.

**Procedure equivalent to USEPA method 330.2 and Standard Methods 4500-Cl.D. for drinking water.

Sample Tips and Techniques

• To avoid loss of chlorine, be careful not to agitate the sample when measuring or pouring.

• Sample glassware must be cleaned and pretreated to satisfy any chlorine demand before the sample is introduced. See Section

7.2 Container Pretreatment on page 63 for additional information.

• Always use organic-free water for sample dilution (Cat. No. 26415-49).

• When sampling tap water, let the faucet run for at least 4–5 minutes prior to collecting the sample.

• A convenient test sample can be prepared by diluting Chlorine Standard Solution (Cat. No. 14268-10) with deionized (DI) water.

• Rinse the electrode, temperature probe, and anti-diffusion tip with deionized water before every titration.

Reagent Tips and Techniques

• Download the “Certificate of Analysis” (COA) to obtain the exact concentration of any unopened bottle of Hach titrant or standard

solution. See Obtaining the Certificate of Analysis for Hach Reagents on page 41.

• Hach buffer reagents for chlorine titrations are highly recommended for this analysis.

• Never substitute buffers designed for calibrating pH meters. They may contain dyes that interfere with amperometric titration.

• Never use buffers contaminated with mold or bacteria.

Instrument Tips and Techniques

• Adjust the contrast of the display by accessing the Methods menu and then pressing 7

• A distinction is drawn between running a new test and a new sample. Each test is a replicate run of the current or previous

sample analysis. The AutoCAT automatically tracks the results of a series of tests, and automatically calculates the mean and standard deviation for all the results. Each test is given a different number, all of which are listed under the same Sample ID. When starting a new sample, a new ID is assigned.

• The AutoCAT can accommodate any sample size. Standard Methods recommends a default volume of 200 mL. The volume can

be adjusted to expand the test range.

• The analysis data may be analyzed repeatedly from the Zoom Range Determination window, in manual (MEPD) and/or automatic

(AEPD) modes. The results are not stored until accepted.

• The AutoCAT calculates the chlorine concentration based on the sample volume. Make sure that the sample volume is correct.

• Press the STOP key any time to interrupt instrument operation. The user will be given the option to resume, restart, or quit.

• Press the CHECK MARK any time during data acquisition to halt data collection.

• Press the DEL key during any timer period (except Start Timer) to immediately exit the timer and proceed to the next step in

the procedure.

• Flush the burette each day before the first sample test or calibration is performed. See Daily Start-up on page 26.

• Flush the burette when changing titrants. See Changing Titrants on page 25.

to lighten or 0 to darken.

Free Chlorine

50081_Chlorine_Free_Forward.fm Page 93

Free Chlorine

Amperometric Titration Free Cl2 - Fwd

1. Access the

methods menu.

Press

2 to choose

Select Method.

5. Place the sample onto

the AutoCAT 9000 stirrer platform.

2. Highlight Free

Cl2-Forward.

Press the

CHECK MARK

to validate.

6. Verify User.

Press the enter a new user or press confirm.

Note: This screen will be skipped if the User ID is disabled. See Setting a User ID on page 27.

CHECK MARK to

1 to

3. Press 1 to select

Run method.

7. Highlight Sample ID.

Press the enter a new sample ID or proceed to step 8.

CHECK MARK to

4. Measure 200 mL of

sample solution into a clean 250 mL beaker.

Insert the specified magnetic stir bar into the sample beaker.

Note: Use only the provided stir bar to minimize loss of chlorine.

8. Highlight

Volume for Test 1.

Press

1 to confirm or press

the

CHECK MARK to enter a

new volume.

Free Chlorine Page 94

50081_Chlorine_Free_Forward.fm

Free Chlorine

9. Add 1.0 mL of pH 7.0

Phosphate Buffer Solution.

Press the confirm and start the timer.

Note: The Phosphate buffer is added to adjust the sample pH. The precise amount added is not crucial for the accuracy or precision of the analysis.

CHECK MARK to

10. The timer will start and

the reagents will mix for a short period before titration begins.

11. Lower the electrode

head onto the beaker rim.

Press the to confirm.

CHECK MARK

12. The analysis parameters

that have been stored for the current Sub-ID may be edited at this time. (Verify Increment from Table 1, “Generator Effluent Condition,” on page 79).

Highlight the appropriate line and press the

CHECK MARK to change one

of the analysis parameters or press 1 to confirm.

Note: Any changes made will become the new default parameters for this method Sub-ID.

Note: These Sub-ID parameters can be edited here as 'run-time' settings, or from the Main Menu as described in Section 3.5.

Note: This step will be skipped if autoscaling software is enabled.

Free Chlorine

50081_Chlorine_Free_Forward.fm Page 95

Free Chlorine

13. The Start Timer will

start.

The electrode will stabilize before data collection.

14. The Zoom Range

Determination window will display the titration curve.

Select and move the cursors to define the range of data points for analysis.

Note: Defining the range of data points allows the user to exclude undesirable portions of the titration curve from the analysis.

15. Select the type of end

point determination.

Press

CHECK MARK for

Automatic. and proceed to step 18 or press Manual.

Note: Automatic determination attempts to identify linear segments without user input.

Note: This screen is not displayed if the Auto-detection software is enabled.

DEL for

16. Use the navigation keys

to select two line segments, one on each side of the titration end point, at the beginning and end of each segment.

Press the confirm changes or press

DEL to return to the previous

window.

Note: For more information on manual EP determination, see page 135.

CHECK MARK to

17. Press the CHECK MARK

to accept the analysis. Proceed to step 19 or press

DEL to return to the previous

window (Zoom range determination) to adjust the linear segments and reanalyze the data.

Free Chlorine Page 96

18. The AutoCAT will

perform the analysis based on the automatic selection of linear segments.

Note: The automated analysis requires approximately 60 seconds to complete.

19. Press the CHECK MARK

to accept the analysis or press

DEL to return to the

previous window (Zoom range determination) to adjust the linear segments and reanalyze the data.

20. The analysis for this test

is complete.

1 to select Continue or

Press

2 to select More Details

press to view analysis statistics specific to the current Sample ID.

50081_Chlorine_Free_Forward.fm

21. Press 1 to select

New Test to perform a replicate sample.

Press

2 to select New Sample

to analyze a new sample with a new ID.

3 to select

Press End Analysis to return to the Methods menu.

Free Chlorine

Method Performance

Table 1 Recommended Volume Increment Settings for Free Chlorine

Estimated Chlorine Conc. (mg/L) Suggested Volume Increment (mL)

0.10–0.30 0.0010

0.30–0.50 0.0100

0.50–1.00 0.0300

1.00–1.50 0.0600

1.50–2.00 0.0900

> 2.000 0.1500

Note: These recommendations apply to Free Chlorine titrations, correspond to data collection times typically under 5 minutes, and provide adequate data points on both sides of the titration end point for proper analysis. Adjusting the volume increment will reduce the data collection times and number of data points collected. For example, doubling the volume increment will cut the data collection time and the number of points collected in half.

Table 2 Precision Statements

At Concentration 95% Confidence Limits

0.277 mg/L Cl

1.924 mg/L Cl

4.942 mg/L Cl

0.251–0.303 mg/L Cl

1.778–2.070 mg/L Cl

4.650–5.234 mg/L Cl

Free Chlorine

50081_Chlorine_Free_Forward.fm Page 97

Free Chlorine

Table 3 Accuracy Assessments

Safety

Summary of Method

Sample Spike Addition Average % Recovery

Drinking Water

Free Cl

at 0.060 mg/L 92.6 (n=4) 87.5–98.0

at 0.220 mg/L 89.7 (n=6) 89.2–92.7

at 0.530 mg/L 91.0 (n=4) 85.4–93.5

% Range of

Recovery

Lower Limit

Titration curve end points are not as sharp as those for Total Chlorine. Therefore, the determination of Free Chlorine concentrations below 0.1 mg/L becomes problematic. As a result, the lower limit for the AutoCAT 9000 has been arbitrarily set to 0.1 mg/L for experimental reasons.

Use good safety practices and laboratory techniques throughout the procedure. Consult the Material Safety Data Sheet (MSDS) for specific reagent(s) information.

This procedure follows method number 4500-Cl D. b. in “Standard Methods for the Examination of Water and Wastewater” (20th Edition). This procedure permits determination of the Free Chlorine concentration in a water sample. Free chlorine corresponds to that portion of chlorine existing either as elemental chlorine (Cl

–

hypochlorous acid (HOCl), or hypochlorite (OCl

) ion.

In the procedure, the sample pH is adjusted to pH 7 by addition of Phosphate buffer. The sample solution is then titrated amperometrically with standard phenylarsine oxide solution.

Required Reagents

Description Qty. required per test Unit Cat. No.

Phenylarsine Oxide (PAO) Titrant, 0.00564 N............................................ varies................ 1000 mL ...............1999-53

Phosphate Buffer, pH 7, w/dropper .............................................................1 mL................. 100 mL ...............21553-32

Required Apparatus

Beaker, Glass, 250-mL................................................................................1 ....................... each......................500-46H

Cylinder, Graduated, 250 mL......................................................................1 ....................... each.........................508-46

Magnetic Stir Bar, Teflon

®*

coated.............................................................1 ....................... each.....................50085-00

Optional Reagents

Chlorine Standard Solution, Voluette® Ampules, 10-mL ...........................varies................ 16/pkg .................14268-10

Dilution water, organic-free ........................................................................varies................ 500 mL ...............26415-49

Optional Apparatus

Mini-printer, thermal, w/cable............................................................................................... each.....................A70P021

*Teflon is a Registered Trademark of EI DuPont Company.

FOR TECHNICAL ASSISTANCE, PRICE INFORMATION AND ORDERING:

In the U.S.A. – Outside the U.S.A. – On the Worldwide Web – ; E-mail –

Page 98 50081_Chlorine_Free_Forward.fm

Call 800-227-4224

toll-free

Contact the HACH office or distributor serving you.

www.hach.com techhelp@hach.com

HACH COMPANY

WORLD HEADQUARTERS Telephone: (970) 669-3050 FAX: (970) 669-2932

Hach AutoCAT 9000 Instruction Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Table of Contents

Section 1 Introduction

1.1 General Information

1.2 Instrument Startup Summary

1.3 Unpacking

1.4 User Access Levels

Section 2 Instrument Assembly

2.2 Instrument Assembly

2.2.1 Attaching the Titrant Bottle Holder

2.2.2 Connecting the Electrode Head and Accessories

2.2.3 Connecting the Titrant Bottle

2.2.4 Assembling the Burette

2.2.5 Connecting the Temperature Sensor

2.2.6 Installing the Electrode

2.2.7 Power Connection

2.2.8 Serial Printer and PC Connections

3.1 Instrument Display and Keypad

Basic Operation

3.2 AutoCAT Main Menus

3.2.1 How to Access the Menus

3.2.2 Methods Menu

3.2.3 Titrants Menu

3.2.4 Electrodes Menu

3.2.5 Cell Menu

3.3 System Configuration

3.3.1 Entering the Supervisor Code

3.3.2 Setting a User ID

3.3.3 Choose a Language

3.3.4 Set the Time

3.3.5 Set the Date

3.3.6 Selecting the ac Power Frequency

3.3.7 Printer Status

3.3.8 Beep ON/OFF

3.3.9 Rules for Routine Access Users

3.3.10 Customizing the Station

3.3.11 Reset to Factory Settings

3.3.12 Exit

3.4 Edition Mode

3.5 Using Sub-ID's

4.1 Accessing Supervisor Mode

Software Setup

4.2 Software Setup for Electrode and Temperature Sensor Installation

4.2.1 Software Setup for Disconnecting or Replacing Electrodes

4.3 Software Setup for Burette Installation

4.3.1 Software Setup for Removing or Replacing the Burette

4.4 Software Setup for Titrant Installation

4.4.1 Software Setup for Switching or Replacing Titrants

4.5 Setting Titrant Concentration

4.6 Obtaining the Certificate of Analysis for Hach Reagents

5.1 Using the AutoCAT 9000 for Amperometric Methods

5.2 AutoCAT Titration

5.2.1 Data Collection

Collecting and Accessing Data

5.2.2 End Point Determination

5.2.3 Parameters Used in the Calculation of the Analyte Concentration

5.2.4 Analysis Calculations

5.2.5 Retrieving Analysis Results from Archives

Calibration Procedures

PAO/5.64 mN

Iodine

7.1 Chlorine

7.2 Container Pretreatment

7.3 Handling

7.4 Samples for Back Titration

Sampling

Titration Procedures

Chlorine Dioxide Generator Yield

Chlorine Dioxide

Free Chlorine