Direct measurement of F-concentration using ion selective electrodes has become a common method for laboratory measurement of F-concentration. Sometimes SPADNS (based on colorimetry ) is also used to measure F-concentration, but the results of F-concentration using ion-selective electrodes are more precise. The method is fast, simple and avoids the interference when using the colorimetric method. Thermo Electron's buffers contain high-valent cations at parts per million levels to remove common interferences.
Recommended Device/Model
F-ion measurement application package (including all accessories and their models) / 1010103
1.4-StarpH/ISE bench meter/1115000
2. F-ion compound electrode/9609BNWP
3. Stirrer (or magnetic stirrer) / 096019
4. Electrode holder/090043
5. Beaker/(50mL)
6. Graduated cylinder / (50mL)
Required solution/type
1.1ppm F-ion standard solution/040906
2.2ppm F-ion standard solution/040907
3.10ppm F-ion standard solution/040908
4. Electrode filling solution, OptimumResultsTMA/900061
5. TISAB II/940909
6. Deionized water
Preparation of Calibration Standards
1. Use a graduated cylinder to measure 25mL of 1ppm (mg/L) F-ion standard solution and pour it into a beaker.
2. Use a graduated cylinder to measure 25mL of 10ppm (mg/L) F-ion standard solution and pour it into a beaker.
sample preparation
1. Use a graduated cylinder to measure 25mL of the sample solution and pour it into a beaker, then use a graduated cylinder to measure 25mL of TISABII (940909) solution and pour it into the same beaker
in the cup.
2. If you need to measure other samples, please repeat the above steps.
result
The measurement results of F-ion content in 5 drinking waters are as follows. This result is somewhat representative:
electrode storage
Short-term storage: Please soak the electrode in 1ppm (mg/L) F-ion standard solution during the measurement interval to avoid filling in the F-ion electrode.
Evaporation of the filling solution leads to crystallization.
Long-term storage: Please refer to the electrode manual.
equipment preparation
F-ion electrode preparation
1. Gently pull off the electrode protective cover and put it away for use.
2. Fill the electrode cavity with electrode filling solution, OptimumResultsTMA.
3. Stand the fill bottle vertically.
4. Insert the tip into the electrode filling solution hole and add a small amount of filling solution. Then stand the electrodes upright.
5. Hold the electrode with one hand, press the electrode cap with your thumb, and discharge a few drops of filling liquid in the electrode to fully wet the inner electrode.
6. Loosen the electrode cap to quickly return the outer electrode body to its original position. If the outer electrode body cannot return to its original position quickly, check whether the O-ring is wet
Wet and repeat steps 4-6 until the outer electrode body can quickly return to its original position. Then replenish the filling liquid to the lower end of the filling liquid hole.
