Hach-Lange ISENO318103 User Manual

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User Manual
Nitrate Probe: Model ISENO318101 or ISENO318103

Safety information

Precautionary labels

Read all labels and tags attached to the instrument. Personal injury or damage to the instrument could occur if not observed. A symbol on the instrument is referenced in the manual with a precautionary statement.
Electrical equipment marked with this symbol may not be disposed of in European public disposal systems after 12 August of 2005. In conformity with European local and national regulations (EU Directive 2002/96/EC), European electrical equipment users must now return old or end-of-life equipment to the Producer for disposal at no charge to the user.
Note: For return for recycling, please contact the equipment producer or supplier for instructions on how to return end-of-life equipment, producer-supplied electrical accessories, and all auxiliary items for proper disposal.

Specifications

Note: Specifications are subject to change without notice.
Specifications Details
DOC022.52
.80031
Probe type Digital combination probe with a non-refillable reference junction and a built-in temperature
sensor
Range 0.1 mg/L (7x10-6 M) to 14,000 mg/L (1 M) Nitrate Nitrogen
Sample pH range pH 2 to 11, must be adjusted to 3 to 5 by Nitrate ISA
Linear region 0.7 mg/L to 14,000 mg/L Nitrate Nitrogen
Slope 58 mV/decade (90 to 110% at 25 °C (77 °F) in linear range per Nernstian theoretical value)
Operating temperature range 0 to 50 °C (32 to 122 °F)
Storage temperature range 5 to 35 °C (41 to 95 °F)
Junction Double junction (ceramic porous pin and annular porous Teflon®)
Reference type Ag/AgCl
Fill solution driTEK Gel (non-refillable)
Response time in linear region < 60 seconds (application dependent)
Minimum sample volume 25 mL
Minimum immersion depth 25.4 mm (1 in.)
Dimensions Diameter: 12 mm (0.47 in.)
Length: 175 mm (6.89 in.)
Cable length: 1 or 3 m (3.28 or 9.84 ft)
Cable connection M12 digital output and connector compatible with HQd meters

Product overview

The ISENO318101 or ISENO318103 probe is a combination temperature sensor (Figure 1). The probe is available with a 1 or 3 m (3.28 or 9.84 ft) cable and is intended for laboratory use. The probe measures nitrate concentration in water samples.
nitrate probe with a built-in
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Figure 1 Probe overview
1 Sensor protection cap 3 Sensing element
2 Reference junction 4 1 or 3 m (3.28 or 9.84 ft) cable

Preparation for use

Prepare the probe for use before calibration or sample measurement.
1. Remove the sensor protection cap from the probe.
2. Rinse the probe with deionized water. Blot dry with a lint-free cloth. Do not touch the
tip of the probe.
Note: Prior to use, the probe must be conditioned for at least five minutes in 25 mL of the lowest concentration standard solution in the calibration set. If probe stabilization is slow after storage, condition the probe for up to one hour in 25 mL of the lowest concentration standard solution in the calibration set.

Calibration

Before calibration:
The probe must have the correct service-life time stamp. Set the date and time in the meter before the probe is attached.
It is not necessary to recalibrate when moving a calibrated probe from one HQd meter to another if the additional meter is configured to use the same calibration options.
Default calibration standard set for ISENO3181 probe requires 1, 10 and 100 mg/L Nitrate as Nitrogen standard solutions. A new method can be made if custom calibration or measurement settings are needed. Refer to Advanced operation on page
To view the current calibration, push , select View Probe Data, then select View Current Calibration.
If any two probes are connected, push the UP or DOWN arrow to change to the single display mode in order to show the Calibrate option.
Prepare the probe for use (refer to Preparation for use on page 2).
7 for a list of additional calibration sets.
Calibration notes:
Stir the standards and samples at a slow and steady rate to prevent the formation of
• a vortex.
Additional standard sets along with the minimum number of calibration points can be selected on the Calibration Options menu.
Push Skip to omit a standard from the calibration routine. The display will not show Skip until the minimum number of standards is met.
Begin with the lowest concentration during calibration. This reduces carry-over contamination to give the best results.
Note the temperatures of the standards during calibration. Keep temperatures between calibration standards within ±2 ºC for optimal results.
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The calibration is recorded in the electrode and the data log. The calibration is also sent to a PC, printer or flash memory stick if connected.
Air bubbles under the sensor tip when submerged can cause slow response or error
• in measurement. If bubbles are present, gently shake the probe until bubbles are removed.
If a calibration error occurs, refer to Troubleshooting on page 10.
Calibration procedure:
1. Connect the
probe to the meter. Make sure that the cable locking nut is securely connected to the meter. Turn the meter on.
6. Add a stir bar and put the probe in the first standard solution in the set. Do not put the probe on the bottom or sides of the container.
2. In three separate beakers or appropriate containers, prepare Nitrate Nitrogen standard solutions (minimum 25 mL volume).
7. Put the beaker on an electromagnetic stirrer and stir at a moderate rate. Check for air bubbles and remove them if necessary.
3. Add the contents of one Nitrate ionic strength adjustment (ISA) powder pillow per 25 mL to each standard.
8. Push Read. The display will highlight the standard value and proceed to the next standard value. The display will show "Stabilizing" and a progress bar as the reading stabilizes. The display shows the standard value when the reading is stable.
4. Push Calibrate. The
display shows the current standard value that is to be read from the standard solution set.
9. Repeat steps 5-8 for the other Nitrate standard solutions in the set.
5. Rinse the probe with deionized water. Blot dry with a lint­free cloth. Do not touch the tip of the probe.
10. Push Done to view the calibration summary. The display will not show Done until the minimum number of calibration points have been collected.
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11. Push Store to
accept the calibration and return to the measurement mode.

Measurement—direct method

Before measurement:
The probe must have the correct service-life time stamp. Set the date and time in the meter before the probe is attached.
If complete traceability is required, enter a sample ID and operator ID before measurement. Refer to the HQd meter manual for more information.
Regular calibration is required for the best measurement accuracy (refer to Calibration on page 2).
Prepare the probe for use (refer to Preparation for use on page 2).
Measurement notes:
Stir the standards and samples at a slow and steady rate to prevent the formation of a vortex.
Stabilization times with smaller concentration changes generally will be longer and can be minimized by proper stirring and conditioning. Experiment to determine the proper stir rate if necessary.
Note the temperatures of the samples during measurement. Temperatures of calibration standards and samples should be kept within ±2 °C of each other for optimal results.
Data is automatically stored in the data log when Press to Read or Interval is selected in the Measurement Mode. When Continuous is selected, data will only be stored when Store is selected.
Between measurements, rinse the probe with deionized water. Blot dry with a lint-free cloth. Do not touch the tip of the probe.
Air bubbles under the sensor tip when submerged can cause slow response or error in measurement. If bubbles are present, gently shake the probe until bubbles are removed.
If a measurement error occurs, refer to Troubleshooting on page 10.
Measurement procedure:
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1. Connect the
probe to the meter. Make sure that the cable locking nut is securely connected to the meter. Turn the meter on.
2. Prepare a minimum of 25 mL of the sample(s) in beakers or appropriate containers. Add the contents of one Nitrate ionic strength adjustment (ISA) powder pillow per 25 mL to each sample.
3. Rinse the probe with deionized water. Blot dry with a lint­free cloth. Do not touch the tip of the probe.
4. Add a stir bar and put the probe in the sample. Make sure that the temperature sensor is fully immersed in the solution. Do not put the probe on the bottom or sides of the container.
5. Put the beaker on an electromagnetic stirrer and stir at a moderate rate. Check for air bubbles and remove them if necessary.
6. Push Read. The display will show "Stabilizing" and a progress bar as the probe stabilizes in the sample. The display will show the lock icon when the reading stabilizes. If required by the application, also record the sample pH and temperature.
7. Repeat steps 2
- 6 for additional measurements.

Low-level measurements

Use the following techniques for measurements at low concentrations
Clean the probe regularly as specified in Maintenance on page 10.
Soak the probe in the lowest concentration standard solution for up to 1 hour before calibration and measurement.
Set the stability criteria to a low value (refer to Change measurement options on page 7).
Stir the standards and samples at a slow and steady rate to prevent the formation of a vortex.
Use a dilute ionic strength adjustor (ISA) solution for calibration and measurements:
8. When measurements are done, store the probe (refer to
Storage
on page
10).
(<1 mg/L NO
3
–N).
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Interferences

1. Dissolve the contents of one ionic strength adjustor powder pillow in 50 mL of
deionized water.
2. Add 5 mL of this solution to every 25 mL of standard or sample that is used.
Note: The ionic strength adjuster can be omitted only when all of the following conditions are true:
The sample does not contain interferences.
The sample pH is in the range that is given in the specifications.
Omission of the ISA is accepted by the regulatory reporting agency (if the measurement is
for regulatory reporting).
The sensing element responds to nitrate as well as other ions. Typically, probe response to another ion increases the potential, and causes a positive error. The response to other ions can be semi-quantitatively determined through the Nikolsky equation, an extended Nernst equation:
E = Eº + (RT/(zF))ln[aNa + KNax × ax]
Where
ax—the activity of the interfering ion
KNax—the selectivity coefficient for the interfering ion relative to nitrate
For the nitrate ISE, the major interferences are shown in Table 1. To eliminate most of these interferences, add the Nitrate ISA and adjust the pH to between 3 and 5. The measurements are usually made at this pH range to eliminate carbonate and bicarbonate interference and reduce organic acid interference.
The selectivity coefficient is the approximate apparent increase in the measured concentration caused by one unit of the interfering ion (e.g., 1 unit of CIO
-
raises the
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nitrate concentration by 0.1). The approximate selectivity coefficients for some ions with the IntelliCAL® Nitrate ISE are shown in Table 1.
Table 1 Interferences
Interference K (selectivity coefficient) value
Perchlorate (CIO
Iodide (I-) 10
Bromide (Br-) 0.1
Chloride (Cl-) 0.006
Nitrite (NO
-
) 1200 (interferes more)
4
-
) 0.001 (interferes less)
2

Run a check standard

The run check standard feature validates instrument performance between sample measurements. Use the run check standard feature for periodic or user-defined interval measurements of a traceable standard solution. Set the criteria for check standards from the ISENO3181
Note: Access control must be off or a valid password must be entered before any of the check standard method options can be changed.
1. Push
2. Select Run Check Standard.
Note: Select the correct probe if two probes are connected to the meter.
3. Prepare the standard solution shown on the display. Add one powder pillow per 25 mL of standard solution.
4. Put the probe in the standard solution and push Read. The display will show "Stabilizing" and a progress bar as the reading stabilizes. The display shows the
Settings menu.
. The Full Access Options menu is shown.
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value of the check standard and either Check Standard Passed or Check Standard Failed.
5. If the display shows Check Standard Passed, the check standard measurement is within the accepted limits set by the administrative user. Select Done to continue with the sample measurement.
6. If the display shows Check Standard Failed, the measurement is outside of accepted limits set by the administrative user and a recalibration is recommended. If the acceptance criteria is set to Cal Expires on Failure: Yes, the display shows the calibration icon and a question mark until the probe is recalibrated. To correct the probe calibration and status indicator, calibrate the probe (refer to Calibration on page

Advanced operation

Parameter-specific settings can be changed through the Full Access Options menu. Details about menu navigation, available options and how to change them are given in the screens, tables and procedures throughout this section.
2).
The settings that can be changed are shown in Table 2.
Table 2 Parameter-specific settings
Setting Options
Measurement Options
Calibration Options
Check Standard Options
Units
Significant digits
Auto stabilization
Stability criteria
Upper and lower range limits
Standard set
Calibration units
Minimum calibration points
Slope limit
Calibration reminder
Standard
Check standard reminder
Acceptance criteria

Change measurement options

Methods are groups of factory-set or user-defined settings relevant to specific applications. If the meter is set to a factory-set method and the Modify Current Settings option is chosen, a prompt for a new name is shown after the changes are entered. The settings are saved with this name to distinguish them from the factory-set methods, which cannot be changed. A saved method can be used instead of multiple adjustments to the individual settings. Changes made to a user-defined method are automatically saved with the existing name. Multiple methods can be saved for the same probe on each meter.
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1. Make sure a probe is connected to the meter.
2. Push and select ISENO3181 Settings.
3. Select Modify Current Settings.
4. Select Measurement Options and update the settings:
Option Description
Chemical Form Sets the concentration value—NO
-
or NO
3
Units Sets the preferred unit for ISE measurements—mg/L (default), µg/L, g/L,
g/kg, mol/L, mmol/L, mol/kg, %, ppm or ppb.
Note: The mV units are shown when the detailed display is selected.
Significant Digits Sets the significant digits shown—2, 3 (default) or 4.
Auto Stabilization Sets auto stabilization—on (default) or off.
The default stability drift rate is 1.0 mV/min.
Stability Criteria When Auto Stabilization is off, sets the stability criteria—0.1 to
9.9 mV/min.
Lower stability criteria will require longer stabilization times, but the
• measurement will be more precise.
Higher stability criteria will require shorter stabilization times, but the measurements may be less precise.
-
-N.
3
Measurement Limits
5. If prompted, enter a name for the new method settings. Additional changes made to
the settings of an existing method are automatically saved with the same method name.
6. Push EXIT until the meter returns to the measurement mode.

Change calibration options

1. Make sure a probe is connected to the meter.
2. Push
3. Select Modify Current Settings.
4. Select Calibration Options and update the settings:
Option Description
Std Set Sets the temperature compensated standard sets that are used for
Sets the measurement limits—Lower limit (default: 0.1 mg/L) or Upper limit (default: 14,000 mg/L).
The measurement limits can be set to match the acceptable values for the sample. When the measurement is above the upper limit setting or below the lower limit setting, the meter shows an "Out of limits" message. This message is an alert to a potential problem with the process conditions.
and select ISENO3181 Settings.
calibration—
10, 100 or 1000 mg/L as NO
1, 10 or 100 mg/L as NO
1, 10, 100 or 1000 mg/L as NO
Standard set values are shown on the Calibration Options screen.
Custom standard sets are characterized at 25 °C (77 °F). Custom standard values are not temperature compensated. Select the Custom buffer to make a custom standard. Up to five standard values can be made .
Note: Only the minimum calibration points must be measured for Done to be shown on the calibration screen.
–N
3
–N
3
–N
3
Chemical Form Sets the chemical form.
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Option Description
Calibration Units
Std Set Values When Std Set is set to Custom, sets the standard set values.
Minimum Cal Points
Slope Limit Sets the slope limit—1 to 30% (acceptable slope criteria, default = 15%).
Sets the preferred unit for ISE Calibration—mg/L (default), µg/L (available only for custom calibration set), g/L, g/kg, mol/L, mmol/L, mol/kg, %, ppm or ppb.
Up to five standard values can be made. Each standard value can include a standard set value, Custom or No Standard.
Sets the minimum number of calibration points necessary before a calibration can be completed—2 or 3.
The slope must fall within set limits for successful calibration.
5. Select Calibration Reminder and update the settings:
Option Description
Reminder Repeat
Expires Calibration expires after the selected time—Immediately, Reminder + 30 min
Meter will make an audible sound when a calibration is due and repeat the sound at the selected interval—Off (default), 2 h, 4 h, 8 h, 2 d, 5 d or 7 d.
(default), Reminder + 1 h, Reminder + 2 h or Continue Reading.
Note: The meter cannot be used to read samples after calibration has expired unless Continue Reading is selected.
6. If prompted, enter a name for the new method settings. Additional changes made to the settings of an existing method are automatically saved with the same method name.
7. Push EXIT until the meter returns to the measurement mode.

Change check standard options

1. Make sure a probe is connected to the meter.
2. Push and select ISENO3181 Settings.
3. Select Modify Current Settings.
4. Select Check Standards Options and update the settings:
Option Description
Standard Sets the check standard—10, 100, 1000 mg/L or Custom.
Standard Units When Standard is set to Custom, sets the preferred unit for ISE check
Standard Value When Standard is set to Custom, enter the standard value using the
5. Select Check Standard Reminder and update the settings:
Option Description
Reminder Sets the check standard reminder—On or Off (default).
Allow Defer Allows the postponement of check standard reminders—Yes or No.
The standard value is shown on the Check Standards Options screen.
standard—mg/L (default), µg/L, g/L, g/kg, mol/L, mmol/L, mol/kg, %, ppm or ppb.
up/down arrow keys.
The meter automatically shows the check standard screen if Reminder is On.
Measurement of the check standard can be delayed if Allow Defer is set to Yes.
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Maintenance

Clean the probe

6. Select Acceptance Criteria and update the settings:
Option Description
Acceptance Limits Sets the tolerance limits for check standard—1% to 20%.
Cal Expires on Failure Recalibration required if check standard fails—Yes or No.
The calibration expires if the check standard fails and Cal Expires is set to Yes.
7. If prompted, enter a name for the new method settings. Additional changes made to the settings of an existing method are automatically saved with the same method name.
8. Push EXIT
until the meter returns to the measurement mode.
Clean the probe when:
Drifting/inaccurate readings occur as a result of contamination on the sensing element or improper storage conditions.
Slow response time occurs as a result of contamination on the sensing element.
The slope is out of range as a result of contamination on the sensing element.
For general contaminants, complete the following steps.
1. Rinse the probe with deionized water. Blot dry with a lint-free cloth. Do not touch the tip of the probe.
2. If harsh contaminants are attached to the probe, polish the probe tip with a soft cloth or cotton swab to remove the contaminants.
3. Soak for 30 minutes in 100 mg/L Nitrate Nitrogen standard solution.

Storage

The probe can be stored dry. To protect the sensing element, rinse with DI water and blot dry with a lint-free cloth. Install the sensor protection cap.
Note: The probe must be conditioned after long-term storage. Refer to Preparation for use on page 2.

Troubleshooting

Message or symptom Possible cause Action
Software not updated To download the most current version of the
software, refer to the applicable product page on the manufacturer's website.
Probe not supported
HQd meter does not support IntelliCAL® probe
Refer to the HQd Series meter manual for the specific instructions for the meter model.
Contact a Technical Support Representative.
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Message or symptom Possible cause Action
Probe not connected properly Disconnect, then connect the probe. Tighten the
locking nut.
Software not updated To download the most current version of the
software, refer to the applicable product page on the
manufacturer's website. Connect a probe or probe requires service
Large number of methods stored on probe.
Damaged probe Make sure connectivity with another electrode or
Refer to the HQd Series meter manual.
Continue to let probe connect. Do not disconnect
probe.
meter to confirm isolated issue with probe. Contact a
Technical Support Representative.
mV reading is the same for all solutions
Slow response time
Slope out of range (refer to
Check probe response
on page 13)
Electrical issue Contact a Technical Support Representative.
Dirty sensing element Clean the probe (refer to Clean the probe
on page
Low sample temperature or temperature difference between samples
Bubbles trapped under sensor tip Gently shake the probe until bubbles are removed
pH is incorrect Make sure the pH is between 3 and 5 after each ISA
Ionic strength adjustor (ISA) not used
Insufficient conditioning Condition for at least 30 minutes in a 100 mg/L
Damaged probe Contact a Technical Support Representative.
Incorrect standards Calibrate using freshly prepared standards.
Dirty sensing element Clean the probe and recalibrate.
Bubbles trapped under sensor tip Gently shake the probe until bubbles are removed
Check the sample temperature. The lower the
temperature or the greater the difference of
temperatures between samples, traditionally the
longer the response time.
from under sensor tip.
addition.
Add ISA to each sample and standard (one powder
pillow per 25 mL of solution).
standard solution with ISA.
from under sensor tip.
10).
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Message or symptom Possible cause Action
Dirty sensing element Clean the probe (refer to Clean the probe
on page
Clogged reference Rinse reference junction with deionized water
thoroughly and shake the probe downward to
remove any air bubbles. The air bubbles will not be
visible.
Improper storage conditions Clean or condition the probe and attempt another
calibration. To re-condition the probe and reference
junctions, allow the probe to soak in a conditioning
solution (that contains ISA) for at least 30 minutes
prior to use.
10).
Drifting/inaccurate readings
Out of range Measurement value is outside of
Out of limits
Stabilization criteria not optimized for the application
Magnetic stirrers may generate sufficient heat to change solution temperature.
Damaged probe Contact a Technical Support Representative.
Electromagnetic Forces (EMF) such as voltaic cells, thermoelectric devices, electrical generators, resistors and transformers
Bubbles trapped under sensor tip Gently shake the probe until bubbles are removed
range
Check standard value is outside of limits set in the current method
Measurement value is outside of measurement limits set in the current method.
Adjust the stabilization criteria in the measurement
options menu.
Put a piece of insulating material between the stirrer
and beaker.
Do not use in areas where EMF is present.
from under sensor tip.
Make sure that the sample is within the range of the
probe.
Make sure that the standard is within the limits of the
current method.
Make another method that expands the acceptable
limits.
Make sure that the sample is within the limits of the
current method.
Make a new method with an expanded range.
Temperature out of range
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Calibration temperature value is outside of range
Measured temperature is outside the range of the electrode.
Check standard temperature value is outside of range
Make sure that the sample temperature is within the
range of the probe.
Make sure that the temperature sensor is working
correctly.
Make sure that the standard temperature is within
the range of the probe.
Make sure that the temperature sensor is working
correctly.
Make sure that the check standard temperature is
within the range of the probe.
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Message or symptom Possible cause Action
Below detection limit
Measurement is not quantifiable with current saved calibration (based on IUPAC-defined practical detection limit).
Measurement value is outside of range.
Perform a new calibration. Check that sample
concentration is bracketed between two standard
solution values (if within linear range).
Re-run calibration and measurement, optimizing
meter settings for slope acceptance and stabilization
criteria for expected sample concentration.
Re-run calibration and sample measurement with
the tips for low-level measurement.
Make sure sample is within the range of the probe.
Check probe response
To make sure there is a probe response, measure the probe potential (in mV) of two Nitrate Standard Solutions that are above and below the expected sample concentration. For example, use 10 and 100 mg/L Nitrate Nitrogen Standard Solutions. The two solutions should have potentials (difference in mV readings) that are 57 mV apart at 25 ºC (within the slope limits of the method is acceptable). Both solutions should be above
3.1 mg/L Nitrate.
Check accuracy of sample reading
To make sure the sample measurement is accurate, add a spike of Nitrate Standard Solution with the volumetric pipet. Refer to Table 3 and formulas to calculate the percent of recovery.
Typically a percent of recovery of 100% ±5% is a good indication that the instrument, technique and the sample do not contribute to measurement errors.
Table 3 Spike reference
Measured sample concentration Volume of standard at add Concentration of standard
1 to 2 mg/L 0.5 mL 100 mg/L
3 to 6 mg/L 1.0 mL 100 mg/L
7 to 15 mg/L 0.3 mL 1000 mg/L
15 to 30 mg/L 0.5 mL 1000 mg/L
30 to 60 mg/L 1.0 mL 1000 mg/L
Percent recovery
Use the following formula to calculate the percent recovery when the sample volume is 25 mL:
E = (C x V1) / V
2
R = (A / (E + S)) x 100
S = mg/L of Nitrate in sample (before spike)
C = concentration of standard used for spiking (mg/L)
V1 = spike volume (mL)
V2 = spike volume (mL) + 25 mL sample volume
E = expected concentration of spike (mg/L)
R = percent recovery
A = actual reading on meter after spike (mg/L Nitrate)
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Willstätterstraße 11 D-40549 Düsseldorf, Germany Tel. +49 (0) 2 11 52 88-320 Fax +49 (0) 2 11 52 88-210 info@hach-lange.de www.hach-lange.de
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Hach Company/Hach Lange GmbH, 2010-2011, 2013. All rights reserved. Printed in U.S.A.
05/2013, Edition 4
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