Calibration and use of PH meters
Turn on the power switch and warm up the instrument for 15 minutes
(1) Measure the temperature of the solution to be tested with a thermometer.
(2) Adjust the temperature knob on the panel of the instrument, so that the scale on the knob is aligned with the pH value of the solution to be measured.
(3) Place the electrode in the solution to be measured, slightly shaken until the digital display is stable to read the pH value, the measurement is complete and make a record.
Precautions before use:
(1) When using for the first time, because the electrode probe is dry, it will affect the measurement accuracy of the instrument, so soak the electrode in 3mol/L potassium chloride solution for 2 hours.
(2) Configuration of 3mol/L KCl solution: weigh 223.65g of KCl and dissolve it in one litre of distilled or deionised water, then dissolve the reagent completely to make 3mol/L KCl solution.
(3) Replace the electrode once a year (the electrode must be replaced regardless of whether it is functional or not).
Calibration
We generally calibrate the pH meter, commonly used "two-point calibration method" that is, select two standard buffer solution pH = 6.86 and pH = 4.00 or pH = 9.18.
For precision level pH meter, in addition to the "positioning" and "temperature compensation" adjustment, there is also an electrode "slope" adjustment. Firstly, pH = 6.86 for "positioning" calibration, and then according to the acid-base situation of the test solution, the choice of pH = 4.00 (acidic) or pH = 9.18 (alkaline) buffer solution for "slope" correction.
