What is PH meter electrode protection solution?
A liquid that protects the electrodes of the pH meter, mainly composed of potassium chloride, preservatives, etc.
Electrode maintenance:
The electrodes used in the laboratory are all composite electrodes, which have the advantages of being easy to use, not affected by oxidizing or reducing substances, and having a fast equilibrium speed. When in use, remove the rubber sleeve on the electrode filling port and the rubber sleeve at the lower end to maintain the hydraulic pressure difference of the potassium chloride solution in the electrode. The following is a brief introduction to the use and maintenance of electrodes:
1. When the composite electrode is not in use, it can be fully soaked in 3M potassium chloride solution. Do not soak with washing liquid or other water-absorbing agents.
2. Before use, check the bulb at the front end of the glass electrode. Under normal circumstances, the electrode should be transparent without cracks; the bulb should be filled with solution without air bubbles.
3. When measuring a solution with a high concentration, shorten the measurement time as much as possible, and wash it carefully after use to prevent the measured liquid from adhering to the electrode and polluting the electrode.
4. After cleaning the electrode, do not wipe the glass membrane with filter paper, but dry it with filter paper to avoid damage to the glass membrane, prevent cross-contamination, and affect the measurement accuracy.
5. Pay attention to the silver-silver chloride internal reference electrode of the electrode during the measurement. When using, pay attention to gently shake the electrode a few times.
6. The electrode cannot be used in strong acid, strong alkali or other corrosive solutions.
7. It is strictly forbidden to use in dehydrating medium such as absolute ethanol, potassium dichromate, etc.
Calibrating pH Meters Using Buffer Solutions
(1) Prepare two 200mL clean beakers, distilled water for cleaning the sensor, pH=4 and pH=7 buffer solutions, and a thermometer for measuring the temperature of the buffer solution.
(2) Pour 50~100mL of pH=4 and pH=7 buffer solutions into beakers respectively.
(3) Remove the sensor from the bracket. If the sensor is installed in the immersion rack, remove the sensor holder together with the protection from the immersion rack.
(4) Clean the sensor electrodes, wipe off the water droplets with absorbent cotton, and immerse the electrodes in the buffer solution with pH=7.
(5) The pH value of the buffer solution changes with the temperature, measure the temperature of the buffer solution with pH=7, and then compare the measured values.
(6) Turn STD (calibration function key) clockwise or counterclockwise until the pH transmitter displays the same value as the value measured in step (5).
(7) Wash off the pH=7 solution on the electrode completely, and immerse the electrode in the buffer solution with pH=4.
(8) Measure the temperature of the pH=4 solution, and compare the measured values.
(9) Adjust SLOPE (electrode response slope) until the pH transmitter displays the same value as the value measured in step (5).
(10) Repeat steps (4)~(6) until the pH transmitter displays the correct value. If the correct pH is read, the buffer calibration is complete.
