Calibration method and procedure for H-meter
The calibration cycle of pH meter is usually 3 months, and the calibration methods and steps are as follows.
(1) Preparation before calibration
① Prepare two beakers, distilled water, standard buffer solutions for low pH and high pH, and a mercury thermometer at 0~100℃.
② Fill one beaker with enough low pH standard buffer solution and the other with enough high pH standard buffer solution.
③ Remove the electrode system from the electrode chamber.
(2) Zero calibration
① Wash the electrode (PH electrode) system with distilled water, dry it with filter paper, and then immerse it in a standard buffer solution of pH 6. 86.
② When the electrode system and the solution temperature balance and transmitter (or converter) indicates the stability of the solution temperature measurement, and according to the "standard buffer solution pH - temperature comparison table" to find out the pH value of the solution at this temperature.
(iii) Adjust the zero (or asymmetric) potentiometer of the meter so that the meter indicates the above pH value.
(3) Range (or slope) calibration (one-point calibration)
The electrode (PH electrode) system is removed from the beaker, washed with distilled water, dried with filter paper and immersed in a standard buffer solution of pH 4.01 or 9. 18. These two buffer solutions are selected based on the principle that the pH value of the solution to be measured and the pH value of the standard buffer solution used for calibration are close to each other.
(4) Range (or slope) calibration
① Remove the electrode system from the beaker, wash it with distilled water, dry it with filter paper, and then immerse it in a standard buffer solution of high pH (pH 4 or pH 9).
② When the electrode system and the solution temperature balance and transmitter (or converter) indicates the stability of the solution temperature measurement}, and according to the "comparison table" to find out the pH value of the solution at that temperature.
(iii) Adjust the range (or slope) potentiometer of the meter to make the meter (PH meter) the above pH value.
(5) Repeat Calibration
Repeat the above zero and range calibration steps until the meter indication is accurate.
