Thermo Fisher Scientific Ion Selective Electrodes Chloride - Manual (Page 5)

Instruction Manual Chloride Electrode
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 20
o
and 25
o
C.
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.
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