Thermo Fisher Scientific Ion Selective Electrodes Chloride - Manual (Page 9)

Instruction Manual Chloride Electrode
Direct Measurement of Chloride (using a ion meter)
1. By serial dilution of the 0.1M or 1,000 ppm chloride standard, prepare two chloride
standards whose concentration is near the expected sample concentration. Measure out 100
ml of each standard into individual 150 ml beakers and add 2 ml of ISA to each.
2.
Place the more dilute solution on the magnetic stirrer and begin stirring at a constant rate.
Assure that the meter is in the concentration mode.
3.
Lower the electrode tips into the solution.
4.
Adjust the meter to the concentration of the chloride standard and fix the value in the
memory according to the meter manufacturer's instructions after stabilization of the
reading.
5. Rinse the electrodes with distilled water and blot dry.
6. Place the more concentrated solution on the magnetic stirrer and begin stirring at a
constant rate.
7.
Lower the electrode tips into the solution.
8.
Adjust the meter to the concentration of the chloride standard and fix the value in the
memory according to the meter manufacturer's instructions after stabilization of the
reading.
9.
For low level measurements, place the rinsed, dried electrodes into the solution containing
100 ml of distilled water and 2 ml of ISA. After stabilization, fix the blank value in the
meter according to the meter manufacturer's instructions.
10. Place 100 ml of the sample and 2 ml of ISA in a 150 ml beaker, place it on the magnetic
stirrer, and begin stirring.
11. Immerse the electrode tips in the solution and wait for the reading to stabilize. Read the
concentration directly from the meter display.
12. The calibration should be checked every two hours. Assuming no change in ambient
temperature, place the electrode tips in the first chloride standard. After the reading has
stabilized, compare it to the original reading in Step 4 above. A reading differing by more
than 0.5 mV or a change in the ambient temperature will necessitate the repetition of Steps
2-8 (9) above. The meter should be re-calibrated daily.
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