The Method of pH Meter Calibration
When a pH meter is not used for a long time, the pH electrode must be activated. The activation method is to soak it in a 3mol KCL solution for 24 hours, rinse it with desalinated water, and then calibrate it with a standard solution. The choice of standard solution should be based on the pH value of the water sample you usually measure.
The following are the calibration methods for pH meters:
1. Firstly, check if the electrode has been consistently immersed in the electrode storage solution
2. Prepare buffer solutions with pH 6.86, pH 4.01, and pH 9.18
3. If the above two points are met, calibration can be carried out
4. Set the mode to the "pH" state
5. Clear previous calibration data: Press the "SETUP" button, the display screen shows "Clear buffer", press the "ENTER" button to confirm
6. Press the "SETUP" button until the display screen shows "1.68, 4.01, 6.86, 9.18, 12.46", and press "ENTER" to confirm.
7. Carefully remove the electrode from the electrode storage solution, rinse the electrode thoroughly with deionized water, and then dry the surface water with filter paper after rinsing (note: do not wipe the electrode).
8. The laboratory pH meter does not require calibration for a long time. The electrode is immersed in a pH 6.86 buffer solution and stirred evenly. When the value stabilizes and an "S" appears, press the "STANDARDIZE" button and wait for the instrument to automatically calibrate. If the calibration time is too long, press the "ENTER" button to manually calibrate. After successful calibration, the calibration point value is stored as , displaying "6.86" and electrode slope information "% SlopeXX". XX displays the measured electrode slope value, which is acceptable within the range of 90-105%. If there is only a greater deviation from the theory, an error message (Err) will be displayed, the electrode should be cleaned, and the above steps should be repeated for recalibration..
9. Remove the electrode, repeat step 3 to clean the electrode, immerse the electrode in a pH 4.01 buffer solution, and repeat step 8. After successful calibration, the value is stored as the second calibration point, displaying (4.016.86) and electrode slope information
