How to use pH combination electrode correctly?
(1) There should be no air bubbles at the front end of the bulb. If there are air bubbles, they should be thrown away with force.
(2) After the electrode is taken out of the soaking bottle, it should be shaken in deionized water and shaken dry. Do not wipe the bulb with paper towels. Otherwise, the electrostatic induction charge will be transferred to the glass membrane, which will prolong the time for the potential to stabilize. A better method is Rinse the electrode with the test solution.
(3) After the pH composite electrode is inserted into the solution to be measured, stir and shake it for a few times before leaving it still. This will speed up the response of the electrode. Especially when using a plastic case pH composite electrode, the stirring and shaking should be more vigorous, because there will be a small cavity between the bulb and the plastic case. After the electrode is immersed in the solution, sometimes the gas in the cavity will not be discharged in time and bubbles will be generated, causing the The contact angle between the bubble or liquid junction and the solution is poor, so vigorous stirring and shaking is required to remove air bubbles.
(4) After testing in a viscous sample, the electrode must be rinsed repeatedly with deionized water several times to remove the sample adhered to the glass film. Sometimes it is necessary to wash the sample with other reagents first, then wash away the solvent with water, and then immerse it in the soaking solution for activation.
(5) Avoid contact with strong acids, alkalis or corrosive solutions. If you test such solutions, you should minimize the immersion time and clean them carefully after use.
(6) Avoid use in dehydrating media such as absolute ethanol and concentrated sulfuric acid, which will damage the hydrated gel layer on the surface of the bulb.
(7) The shell material of the plastic pH composite electrode is polycarbonate plastic (PC). PC plastic will dissolve in some solvents, such as carbon tetrachloride, trichlorethylene, tetrahydrofuran, etc. If the above solvents are included in the test, it will Electrode shell, in this case, a pH composite electrode with a glass shell should be used instead.
