The role of pH meter temperature compensation
The temperature compensation of the pH meter should include three parts: the temperature compensation of the electrode slope, and the temperature compensation of the electrode zero point (including the measuring electrode and the reference electrode). The temperature compensation set on the pH meter is only the slope item of the compensation electrode (2.303RT/F). Therefore, temperature compensation is not very sufficient for pH meter measurements, nor can it completely eliminate errors caused by temperature. Only because the temperature item of the solution and the zero point temperature item of the electrode can not be determined, and the error caused by it is very small, so it is omitted.
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2. Common sense of pH electrode calibration
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After the pH electrode is used for a period of time, the asymmetry potential will change greatly, so it must be calibrated regularly.
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The frequency of pH meter electrode calibration and calibration depends on the sample, electrode performance and accuracy requirements for measurement. For high-precision measurement (≤±0.03pH), it should be calibrated in time; for general precision measurement (≤±0.1pH), it can be used continuously for two weeks or even longer after one calibration.
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There is absolutely no need to frequently recalibrate the electrode as long as the measurement shows that the pH is accurate. First test the standard solution that is closer to the measured solution, and determine whether recalibration is required according to the size of the error.
