Factors Affecting Measurement Error of Online pH Meters
One of the common electrochemical analysis instruments in pH chemistry laboratories. But users are prone to significant errors and malfunctions during use. The following are the factors that affect the measurement error of online pH meters summarized by the Qingdao office of Shanghai Kuosi Electronics Co., Ltd.:
1. Verification of online pH meter
When laboratory personnel use a pH meter to measure the pH value of a solution, if they do not trust the measured results, they can use the following method to distinguish, that is, to measure one or two pH standard solutions. If the error of the measured pH standard solution is very small, it indicates that the pH acidity meter measurement result is reliable. On the contrary, if there is a large error in measuring the pHs standard solution, it indicates that there is a problem with the pH meter, pH electrode, and part of the pHs standard solution. Check them one by one according to the following methods.
(1) For electric meters, in addition to obvious faults, attention should be paid to the following issues: firstly, the temperature compensator should be placed accurately, and the rotation should not be loose; The second is a pH meter with slope correction. When using the one point positioning method to measure a solution, the slope should be placed at the 100% position; The third is to pay attention to whether the glass pH electrode socket is in good contact.
(2) For a pH glass electrode in an electrode, it should be checked whether the silver chloride reference electrode is immersed in the solution inside the glass electrode. For the calomel electrode, attention should be paid to whether there are bubbles inside the tube, whether the salt bridge is blocked, and whether the contact piece of the calomel electrode is oxidized. Good pH electrodes can also be used to replace measurements one by one for discrimination.
(3) For the pH standard solution of the pH meter, it should be re prepared, and a calibrated pH acidity meter can also be used to measure and distinguish the error of the standard solution. In general, the possibility of significant errors in the pH standard solution is small.
