pH meter common problems and solutions
Is the pH value of the same sample different between two measurements?
Temperature changes or chemical reactions within the sample itself can cause changes in pH value. So, it is advisable to maintain consistent temperature and avoid chemical reactions as much as possible.
2. The same sample is measured on two pH meters at the same time, but the readings are inconsistent?
Due to the different calibration conditions of the two pH meters (such as calibration performed at different times), there are differences in the measured values. So it is necessary to calibrate the pH meter with the same buffer solution at the same time, and then measure it simultaneously.
Why has the buffer deteriorated within its expiration date and cannot be used?
The shelf life of buffer solution refers to the storage period in an unopened state. Once opened and used, the buffer solution is prone to spoilage due to the effects of various molds in the air.
Attention: Do not pour the used buffer back into the original bottle!
How often do electrodes need to be calibrated?
The calibration frequency of electrodes depends on specific factors such as electrode usage, maintenance, sample properties, and measurement accuracy. It is recommended to calibrate once a day, with a maximum of once a week. Electrode replacement and prolonged disuse must be calibrated before use.
5. How to maintain pH electrodes?
After using the electrode for a period of time, if you find that the slope decreases or the response speed slows down, you can try the following methods:
① If the measured sample contains proteins, the electrode membrane can be cleaned with gastric protease/hydrochloric acid wash solution.
② If the measured sample is an oily/organic liquid, it can be washed with acetone or ethanol.
③ If the electrode liquid network becomes dirty and black, thiol cleaning solution can be used to clean the liquid network.
④ Activate the electrode membrane, activation method: soak the electrode regeneration solution for 30 seconds, and then soak it in a 3mol/L KCl solution for 5 hours.
