Self-calibration and storage of pH electrodes
Issues to consider while using a pH meter (acidity meter) include: The integrity of the electrode should be examined first before use.
1: Check to see if the glass bulb is fractured or broken before using the pH closed composite electrode. If not, it is often regarded as acceptable when using the pH buffer solution for two-point calibration and the positioning and slope buttons can be changed to the corresponding pH value. Instead, the electrode activation therapy can be performed in accordance with the handbook.
(1) The pH electrode activation procedure involves soaking it in 4% hydrogen fluoride solution for about 3 to 5 seconds, removing it, rinsing it with purified water, and then calibrating it in 0.1mol/L hydrochloric acid solution. Use a buffer solution with a pH of 6.86 (25°C) for positioning, in other words. After adjusting the slope, select a different pH buffer solution. The electrode must be changed if it cannot be adjusted.
The external reference solution for the PH non-closed composite electrode is 3 mol/L potassium chloride solution, so it is required to check whether the electrode's potassium chloride solution content is greater than 1/3. If it is not, 3 mol/L potassium chloride solution should be added. If the potassium chloride solution rises above the location of the small hole, shake off the extra solution until it is below the small hole, then inspect the solution for bubbles. If bubbles are present, flick the electrode to entirely eliminate them.In order to use the electrode, the rubber covering it must be peeled off to reveal a tiny hole. If not, a negative pressure will be created during the analysis, preventing the potassium chloride solution from passing through the glass bulb to exchange ions with the measured solution. will lead to erroneous measurement data. The rubber should be replaced after the measurement is finished to close the little hole.
3. To keep the electrode bulb wet, the pH electrode should be washed with distilled water and then soaked in a 3 mol/L potassium chloride solution. To get the electrode to the best measuring state, let it sit in the solution for a few hours. In practice, it has been observed that some analysts treat the composite electrode like a glass electrode and give it a lengthy bath in distilled water. This is wrong because it will significantly lower the amount of potassium chloride solution in the composite electrode, which would lead to The composite electrode shouldn't be left in distilled water for an extended period of time since the electrode reaction is not sensitive during measurement, which may eventually result in false measurement data.
