Calibration method of acidity meter (pH meter)
The acidity meter is referred to as the pH meter, which consists of two parts: an electrode and an electric meter. If the electrode can be properly maintained, the standard buffer solution can be prepared according to the requirements and the electric meter can be operated correctly, the pH indication error can be greatly reduced, thereby improving the reliability of chemical experiments and medical test data.
Although there are many types of pH meter, its calibration method adopts two-point calibration method, that is, two standard buffers are selected: one is pH7 standard buffer, the second is pH9 standard buffer or pH4 standard buffer. First, use the pH7 standard buffer to locate the electrometer, and then select the second standard buffer according to the acidity and alkalinity of the solution to be tested. If the solution to be tested is acidic, select pH4 standard buffer; if the solution to be tested is alkaline, select pH9 standard buffer. If the pH meter is manually adjusted, it should be operated several times between the two standard buffers until it is no longer necessary to adjust its zero point and positioning (slope) knob, and the pH meter can accurately display the pH values of the two standard buffers. The calibration process ends.
After this, the zero and positioning knobs should not be moved during the measurement. If it is an intelligent pH meter, it does not need to be adjusted repeatedly, because the pH value of several standard buffers has been stored in it to choose from, and it can be automatically recognized and calibrated automatically. But pay attention to the accuracy of standard buffer selection and its preparation. Smart pH. Secondly, special attention should be paid to the temperature of the solution to be measured before the pH meter is calibrated. In order to select the standard buffer correctly, and adjust the temperature compensation knob on the electric meter panel to make it consistent with the temperature of the solution to be tested. At different temperatures, the pH of standard buffer solutions is different.
