Thermo Fisher Scientific Ion Selective Electrodes Copper - Manual (Page 6)

Instruction Manual Copper Electrode
6
3. Using a pipette, add 10 ml of the standard used above
to the beaker. When the reading is stable, record the
millivolt reading.
4. Determine the difference between the two readings. A
difference of 27
∀2 mV indicates correct electrode
operation, assuming the temperature is between 20
o
and
25
o
C. See the TROUBLESHOOTING GUIDE and
TROUBLESHOOTING HINTS sections 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.
Electrode Slope Check (with ion meter)
(check electrodes each day)
1. Prepare standard cupric solutions whose concentrations
vary be tenfold. Use either the 0.1M or 1000 ppm stock
solutions and 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 a
magnetic stirrer and begin stirring at a constant rate.
After assuring that the meter is in the concentration
mode, lower the electrode tip(s) into the solution.
3. After the reading has stabilized, 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 electrode(s) with distilled water and blot
dry.
5. To a 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 tip(s) into the solution.
6. After the reading has stabilized, 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%. If the
slope is not within this range, see the TROUBLESHOOTING
GUIDE
and TROUBLESHOOTING HINTS sections.