Usage and Maintenance of pH Meter Electrodes
1. The electrode must be calibrated with a standard buffer solution with a known pH value before measurement, and the closer its pH value is to the measured pH value, the better.
2. Before performing the next operation after each calibration or measurement, the electrode should be thoroughly cleaned with distilled water or deionized water, and then cleaned once with the test solution.
After removing the electrode sheath, the sensitive glass bubbles of the electrode should be avoided from coming into contact with hard objects, as any damage or scratching will cause the electrode to fail.
4. After the measurement is completed, promptly put on the electrode protective cover. A small amount of external reference supplement solution should be placed inside the electrode cover to keep the electrode bubbles moist, and avoid soaking them in distilled water.
5. The external reference supplement solution for the composite electrode is a 3mol/L potassium chloride solution. The supplement solution can be added through a small hole at the top of the electrode. When the composite electrode is not in use, pull on the rubber sleeve to prevent the supplement solution from drying up.
6. The lead out end of the electrode must be kept clean and dry to prevent short circuits at both ends of the output, otherwise it will cause measurement errors or failures.
7. The electrode should be paired with a pH meter with a high input impedance (≥ 1012 Ω) to maintain good characteristics.
8. The electrode should avoid prolonged immersion in distilled water, protein solutions, and acidic fluoride solutions.
9. Avoid contact between electrodes and organic silicone oil.
After long-term use, if the slope of the electrode slightly decreases, the lower end of the electrode can be soaked in 4% HF for 3-5 seconds, washed with distilled water, and then soaked in a 0.1mol/L hydrochloric acid solution to restore it.
If the tested solution contains substances that can easily contaminate sensitive bubbles or block the liquid interface, causing electrode passivation, the slope will decrease and the display reading will be inaccurate. If this phenomenon occurs, the electrode should be cleaned with an appropriate solution according to the nature of the pollutant to restore its original state.
