How often should pH meters be calibrated if their results fluctuate?
The pH meter reading is inaccurate, how often should the acidity meter be calibrated? The reason for inaccurate readings can be found from two aspects: the operation process of the pH electrode and the maintenance process.
1. Detailed analysis of pH meter electrodes
1) Whether the calibration is done well before the measurement; if the calibration is not good once, you can repeat the calibration, refer to the 3-point calibration in the manual of the Ziman instrument. "How should I do the third point calibration of the pH meter?" If it is impossible to calibrate, consider changing the electrode.
2) The electrode bulb is polluted and needs to be cleaned properly: if the measured solution contains substances that are easy to contaminate the sensitive bulb or block the liquid junction and passivate the electrode, the slope will decrease and the displayed reading will be inaccurate. If this phenomenon occurs, it should be cleaned with an appropriate solution according to the nature of the pollutant to restore the electrode. For cleaning steps, please refer to the above official website.
3) Before immersing the electrode in each solution to be tested, it should be washed with distilled water, and the adherent liquid should be carefully absorbed with absorbent paper to avoid contamination and dilution of the tested solution, resulting in inaccurate measurement and analysis.
2. Simplified analysis
1) The probe of the pH meter is dirty and should be cleaned.
2), the wiring is loose
3), PH meter aging
4), the measured liquid fluctuates greatly
3. The main reason is that the number of ions in the solution is too small, resulting in unstable readings, such as pure water, of course, it may also be a problem with the instrument
1) The pH meter is not cleaned and there are residual reagents
2) There is a reaction in the solution. 3. The solution is not shaken well
4. How often does the acidity meter need to be calibrated to distinguish whether you are using it in industry or a laboratory pH meter.
1) In industrial use, if the solution medium is being measured all the time, then there is no need to calibrate. If it is removed from the original package and then put back in, it needs to be recalibrated or calibrated.
2) The laboratory uses a laboratory pH meter, which is required to be more accurate. Of course, each experiment you do is different, so you must recalibrate it before each use.
