Introduction to calibration and use of pH meter
1. Use
Turn on the power switch and preheat the instrument for 15 minutes
(1) Use a thermometer to measure the temperature of the solution to be measured
(2) Adjust the temperature knob on the instrument panel so that the scale line on the knob is aligned with the temperature of the solution to be measured.
(3) Place the electrode in the solution to be measured, shake it slightly until the digital display stabilizes and read the pH value. Complete the measurement and record it.
Precautions before use:
(1) When used for the first time, since the electrode probe is relatively dry, which will affect the measurement accuracy of the instrument, first soak the electrode in 3mol/L potassium chloride solution for 2 hours.
(2) Preparation of 3mol/L potassium chloride solution: Weigh 223.65g of potassium chloride and dissolve it in one liter of distilled or deionized water. Completely dissolve the reagent to obtain a 3mol/L potassium chloride solution.
(3) Replace the electrode once a year (the electrode must be replaced regardless of whether it is usable).
2. Calibration
We generally calibrate pH meters, using the "two-point calibration method", that is, selecting two standard buffer solutions, pH=6.86 and pH=4.00 or pH=9.18.
For precision-grade pH meters, in addition to "positioning" and "temperature compensation" adjustments, there is also an electrode "slope" adjustment. First use pH=6.86 for "positioning" calibration, and then select pH=4.00 (acidic) or pH=9.18 (alkaline) buffer solution for "slope" calibration according to the acid-base condition of the test solution.
