Eutech Instruments CHLORIDE EPOXY User Manual

Instruction Manual Chloride Electrode

EUTECH INSTRUMENTS PTE LTD.

INSTRUCTION MANUAL

CHLORIDE ION ELECTRODE

Instruction Manual Chloride Electrode

TABLE OF CONTENTS

GENERAL INSTRUCTIONS ..........................................................................................................3

Introduction..............................................................................................................................................4

Required Equipment.................................................................................................................................4

Required Solutions................................................................................................................................... 4

GENERAL PREPARATION............................................................................................................5

Electrode Preparation...............................................................................................................................5

Electrode Slope Check (with pH/mV meter) ...........................................................................................5

Electrode Slope Check (with ion meter)..................................................................................................6

MEASUREMENT..............................................................................................................................6

Measuring Hints....................................................................................................................................... 6

Sample Requirements...............................................................................................................................7

Units of Measurement..............................................................................................................................7

MEASUREMENT PROCEDURE ................................................................................................... 7

Direct Measurement.................................................................................................................................7

Direct Measurement of Chloride (using a pH/mV meter)........................................................................7

Direct Measurement of Chloride (using a ion meter)...............................................................................9

Low Level Chloride Determination (using a pH/mV meter).................................................................10

Low Level Chloride Determination (using an ion meter)......................................................................11

ELECTRODE CHARACTERISTICS........................................................................................... 11

Reproducibility.......................................................................................................................................11

Interferences...........................................................................................................................................11

Removal of Various Interferences with CISA .......................................................................................12

Complexation.........................................................................................................................................12

Temperature Influences..........................................................................................................................13

Electrode Response................................................................................................................................13

Limits of Detection ................................................................................................................................15

pH Effects ..............................................................................................................................................15

Electrode Life.........................................................................................................................................15

Electrode Storage...................................................................................................................................15

ELECTRODE THEORY................................................................................................................16

Electrode Operation ...............................................................................................................................16

TROUBLESHOOTING GUIDE....................................................................................................17

Meter......................................................................................................................................................17

Glassware...............................................................................................................................................17

Electrodes...............................................................................................................................................17

Standards and Reagents..........................................................................................................................18

Sample....................................................................................................................................................18

Technique...............................................................................................................................................18

TROUBLESHOOTING HINTS.....................................................................................................19

SPECIFICATIONS..........................................................................................................................21

ORDERING INFORMATION.......................................................................................................21

Instruction Manual Chloride Electrode

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Introduction............................................................................................................Error! Bookmark not defined.

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Required Solutions.................................................................................................Error! Bookmark not defined.

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Electrode Slope Check (with pH/mV meter)....................................................E

Electrode Slope Check (with ion meter) ..........................................................E

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MEASUREMENT.............................................................................................. Error! Bookmark not defined.

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Sample Requirements.......................................................................................E

Units of Measurement......................................................................................E

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Direct Measurement.........................................................................................ERROR! BOOKMARK NOT DEFINED.

Direct Measurement of Silver (using a pH/mV meter)....................................E

Direct Measurement of Silver (using an ion meter).........................................E

Direct Measurement of Sulfide (using a pH/mV meter)..................................E

Direct Measurement of Sulfide (using an ion meter).......................................E

Low Level Silver Determinations (using a pH/mV meter)..............................E

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Titration of Silver.............................................................................................E

Low Level Chloride Titration .......................................................................... E

Indicator Titration ............................................................................................E

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ELECTRODE CHARACTERISTICS............................................... Error! Bookmark not defined.

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Interference ......................................................................................................E

Complexation...................................................................................................E

Temperature Influences....................................................................................E

Electrode Response..........................................................................................E

Limits of Detection...........................................................................................E

pH Effects.........................................................................................................E

Electrode Life...................................................................................................E

Electrode Storage .............................................................................................E

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TROUBLESHOOTING GUIDE........................................................ Error! Bookmark not defined.

Meter................................................................................................................ERROR! BOOKMARK NOT DEFINED.

Glassware.........................................................................................................E

Electrodes.........................................................................................................E

Standards and Reagents....................................................................................E

Sample..............................................................................................................E

Technique.........................................................................................................E

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Instruction Manual Chloride Electrode

EUTECH INSTRUMENTS PTE LTD.

CHLORIDE ION ELECTRODE

INSTRUCTION MANUAL

GENERAL INSTRUCTIONS

Introduction

Eutech Instruments Chloride Ion Electrode is used to measure chloride ions in aqueous solutions quickly, simply, accurately, and economically.

Required Equipment

1. A pH/mV meter or an ion meter, either line operated or portable.

2. Semi-logarithmic 4-cycle graph paper for preparing calibration curves when using the meter in the mV mode.

3. A magnetic stirrer.

4. Eutech Chloride Ion Combination Epoxy-body Electrode, Code no. EC-CLO-03.

5. Polishing Paper, Code no. EC-MIS-PP, to polish dirty or etched electrode membranes.

Required Solutions

1. Deionized or distilled water for solution and standard preparation.

2. Eutech Ionic Strength Adjuster (ISA), 5M NaNO solution from your own laboratory stock, half fill a 1,000 ml volumetric flask with distilled water and add 425 grams of reagent-grade sodium nitrate, NaNO dissolve the solid. Fill the flask to the mark with distilled water, cap, and invert the flask several times to mix the contents. ISA is added at the rate of 2 ml of ISA to each 100 ml of standard or sample to adjust the ionic strength to about 0.1M.

3. Eutech Electrode Filling Solution, 1M/0.1M KNO3/KCl, Code no. EC-RE-018, for the ECCLO-03 chloride combination epoxy electrode. Eutech Electrode Filling Solution, 1M KNO3 Code No. EC-RE-013, for the ECR-04-HC double junction reference electrode or the EC-CLO-02 chloride combination glass electrode.

4. Eutech Chloride Standard, 0.1M NaCl, Code no. EC-SCS-CL1-BT. To prepare this solution from your own laboratory stock, add 5.84 grams of reagent-grade sodium chloride, NaCl, to a one liter volumetric flask about half-full of distilled water. Swirl the flask to dissolve the solid. Fill to the mark with distilled water, cap, and upend the flask several times to mix the solution.

, Code no. EC-ISA-CL1. To prepare this

. Swirl the flask to

Instruction Manual Chloride Electrode

5. Eutech Chloride Standard, 1,000 ppm Cl-1, Code no. EC-SCS-CL2-BT. To prepare this solution from your own laboratory stock, add 1.65 grams of reagent-grade sodium chloride, NaCl, to a one liter volumetric flask about half-full of distilled water. Swirl the flask to dissolve the solid. Fill to the mark with distilled water, cap, and upend the flask several times to mix the solution.

6. Eutech Chloride Standard, 100 ppm Cl-1, Code no. EC-SCS-CL3-BT. To prepare this solution from your own laboratory stock, add 0.165 grams of reagent-grade sodium chloride, NaCl, to a one liter volumetric flask about half-full of distilled water. Swirl the flask to dissolve the solid. Fill to the mark with distilled water, cap, and upend the flask several times to mix the solution.

GENERAL PREPARATION

Electrode Preparation

Remove the rubber caps covering the electrode tips and the rubber insert covering the filling hole of the reference electrode. Fill the combination electrode or the reference electrode with the filling solution shipped with the electrode to a level just below the fill hole. No preparation is required with a sealed reference electrode. Connect the electrodes to the proper terminals of the meter as recommended by the meter manufacturer.

Electrode Slope Check (with pH/mV meter)

(Check electrodes each day)

1. To a 150 ml beaker, add 100 ml of distilled water and 2 ml of ISA. Place the beaker on a magnetic stirrer and begin stirring at a constant rate. After assuring that the meter is in the mV mode, lower the electrode tips into the solution.

2. Using a pipet, add 1 ml of 0.1M or 1,000 ppm chloride standard to the beaker. When the reading has stabilized, record the millivolt reading.

3. Using a pipet, add 10 ml of the same chloride standard used above to the beaker. When the reading has stabilized, record the millivolt reading.

4. Determine the difference between the two readings. A difference of -57±3 mV indicates correct electrode operation, assuming the solution temperature is between 20o and 25oC. See the TROUBLESHOOTING section if the potential change is not within this range.

Slope is defined as the change in potential observed when the concentration changes by a factor of

10.

Instruction Manual Chloride Electrode

Electrode Slope Check (with ion meter)

(Check electrodes each day)

1. Prepare standard chloride solutions whose concentrations vary by tenfold. Use either the

0.1M or 1,000 ppm chloride standard. Use the serial dilution method for this preparation.

2. To a 150 ml beaker, add 100 ml of the lower value standard and 2 ml of ISA. Place the beaker on the magnetic stirrer and begin stirring at a constant rate. Lower the electrode tips into the solution. Assure that the meter is in the concentration mode.

3. Adjust the meter to the concentration of the standard and fix the value in the memory according to the meter manufacturer's instructions.

4. Rinse the electrodes with distilled water and blot dry.

5. To another 150 ml beaker, add 100 ml of the higher value standard and 2 ml of ISA. Place the beaker on the magnetic stirrer and begin stirring at a constant rate. Lower the electrode tips into the solution.

6. Adjust the meter to the concentration of the standard and fix the value in the memory.

7. Read the electrode slope according to the meter manufacturer's instructions. Correct electrode operation is indicated by a slope of 90-100%. See the TROUBLESHOOTING section if the slope is not within this range.

MEASUREMENT

Measuring Hints

All samples and standards should be at the same temperature for precise measurement. A difference

C in temperature will result in about a 2% measurement error.

of 1

Constant, but not violent, stirring is necessary for accurate measurement. Magnetic stirrers can generate sufficient heat to change the solution temperature. To counteract this effect, place a piece of insulating material, such as styrofoam sheet, between the stirrer and beaker.

Always rinse the electrodes with distilled water and blot dry between measurements. Use a clean, dry tissue to prevent cross-contamination.

For samples with high ionic strength, prepare standards whose composition is similar to the sample. Always check to see that the membrane is free from air bubbles after immersion into the standard or sample.

Instruction Manual Chloride Electrode

Sample Requirements

All samples must be aqueous and not contain organics which can dissolve the epoxy electrode body and/or the cement bonding the sensing crystal to the electrode body. Infrequent measurements in solutions containing methanol, ethanol, benzene, and acetonitrile are permitted. Highly polar solvents slowly attack the electrode. Please check with Eutech Instruments Pte Ltd. before using the electrode in other organic solvents. The temperature of the standard solutions and of the sample solutions should be the same and

below 50

Interferences should be absent. If they are present, use the procedures found in the

Interferences

and Electrode Response sections to remove them.

The pH range for the chloride ion electrode is 2-12. Neutralize samples outside this range with acid or base to bring them in range.

Units of Measurement

Chloride concentrations are measured in units of parts per million, equivalents per liter, moles per liter, or any other convenient concentration unit. Table 1 indicates some of the concentration units.

TABLE 1: Concentration Unit Conversion Factors

ppm Cl-1 moles/liter Cl

-1

354.50 1.0X10-2

35.45 1.0X10-3

3.55 1.0X10-4

MEASUREMENT PROCEDURE

Direct Measurement

Direct measurement is a simple procedure for measuring a large number of samples. A single meter reading is all that is required for each sample. The ionic strength of samples and standards should be made the same by adjustment with ISA for all chloride solution. The temperature of both sample solution and of standard solutions should be the same.

Direct Measurement of Chloride (using a pH/mV meter)

1. By serial dilution of the 0.1M or 1,000 ppm standards, prepare 10-2, 10-3, and 10-4M or 100 and 10 ppm chloride standards. Add 2 ml of ISA per 100 ml of standard. Prepare standards with a composition similar to the samples if samples have an ionic strength above 0.1M.

-4

2. Place the most dilute solution (1.0x10

M or 10 ppm) on the magnetic stirrer and begin stirring at a constant rate. After assuring that the meter is in the mV mode, lower the electrode tips into the solution. When the reading has stabilized, record the mV reading.

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