A pH meter is an instrument that measures the pH of a solution. The main body of the pH meter is a precision potentiometer. When measuring, the composite electrode is inserted in the solution to be measured, different electromotive force is generated due to the difference in acidity (hydrogen ion concentration) of the solution to be measured, it is amplified by a DC amplifier, and finally the measured solution is indicated by a reading indicator (voltage meter). The pH value. The pH meter can be used in the 0-14 pH range.

Acidity meter has a variety of desktop, portable, table type and other reading indicators are digital and analog.

1 Calibration: Adjust the slope regulator of the instrument to 100%, and then adjust the temperature regulator to the temperature according to the temperature of the tested solution.

2 Positioning: Insert the composite electrode into the instrument. Select a buffer solution that is closest to the pH of the sample, place the electrode in this buffer, shake the beaker, and homogenize the solution. When the reading is stable, the reading should be the pH of the buffer solution, otherwise the positioning regulator will have to be adjusted. For assays with higher analytical accuracy requirements, two buffer solutions are selected (ie, the pH of the sample being tested is between or close to the pH values ​​of the two buffer solutions). After the pH reading of the buffer solution is stabilized, the reading should be the pH of the buffer solution, otherwise the positioner is adjusted. Rinse the electrode and dry the remainder of the electrode bulb surface. Put the electrode into the second buffer solution and shake the beaker to make the solution uniform. After the reading is stable, the reading should be the pH of the second buffer solution, otherwise adjust the slope regulator.

3 Measurement: pH-calibrated instruments can be used to determine the pH of a sample. At this time, the temperature regulator, positioning regulator, and slope regulator can no longer move. After cleaning the electrode with distilled water, dry the electrode ball portion with filter paper, insert the electrode into the beaker containing the sample to be measured, gently shake the beaker, and after the reading is stable, the pH of the sample to be measured is displayed.