25
Fluoride Ion Selective Electrode User Guide
Single Known Addition Using a Meter with a Known
Addition Mode
Note:
See the meter user guide for more specifi c information.
1. Set up the meter to measure in the known addition mode.
2. Measure 50 mL of the sample and 50 mL of TISAB II or
5 mL of TISAB III and add to a beaker. Rinse the electrode
with deionized water and place it into the sample solution.
Stir the solution thoroughly.
3. When a stable reading is displayed, set the meter as
described in the meter user guide, if required.
4. Pipette the appropriate amount of the standard solution into
the beaker. Stir the solution thoroughly.
5. When a stable reading is displayed, record the sample
concentration.
Single Known Addition Using a Meter with a Millivolt Mode
1. Set the meter to relative millivolt mode. If a relative
millivolt mode is not available, use the millivolt mode.
2. Measure 50 mL of sample and 50 mL of TISAB II or 5 mL
of TISAB III and add to a 150 mL beaker. Stir the solution
thoroughly.
3. Rinse the electrode with deionized water, blot dry and place
into the beaker. When a stable reading is displayed, set the
meter to read 0.0 mV. If the reading cannot be adjusted to
0.0 mV, record the actual mV value.
4. Pipette the appropriate amount of standard solution into the
beaker. Stir the solution thoroughly.
5. When a stable reading is displayed, record the mV value.
If the meter could not be set to 0.0 mV in step 3, subtract
the fi rst reading from the second reading to calculate ΔE.
Note:
Double known addition method is outlined in the Dual
Star meter manual.
