How to correct the pH meter

How to correct the pH meter?

1. Prepare 6.86 pH, 4.00 pH, 9.18 pH standard buffer solution with fresh distilled water, buy the acidity timer, use up to buy at the chemical instrument store, very cheap, a few cents a pack;

2. Power on the pH meter and warm it up for 30 minutes to ensure that the value is stable;

3. Select the temperature compensation in the standard buffer solution temperature, usually the ambient temperature;

4. Calibration Positioning: Soak the electrode in a 6.86 pH solution for a few minutes. After the value is stable, adjust the position of the instrument so that the value is displayed as the pH value at that temperature, which is approximately between 6.95 pH and 6.84 pH. (Check the purchase pH. When the standard material has a pH~temperature table, positioning correction is completed;

5. Correct slope: If the pH is measured with 4.00 pH, and the alkali is measured with 9.18 pH, remove the electrode from the 6.86 pH solution and rinse with distilled water several times. Dry the moisture with a clean absorbent paper and place in a 4.00 pH or 9.18 pH solution for several minutes. After the value is stable, adjust the slope of the instrument so that the value is displayed as the pH at the temperature (see the table), and the slope correction is completed;

6. After removing the electrode from the 4.00pH or 9.18pH solution, rinse it several times with distilled water, blot it with clean absorbent paper, and put it into the solution for a few minutes.

7.0.1 and 0.2 below the pH meter can be corrected positioning, slope can be corrected (some cheap low-precision acidometer only positioning correction), 0.01, 0.02, 0.001 acidity meter needs to correct the positioning and slope.

8. If the pH meter electrode cannot be stably read in more than ten minutes, the electrode needs to be changed, usually one year. If a thick solution is measured, it must be replaced even for several weeks.