How to calibrate and use a pH meter
Turn on the power switch and preheat 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 instrument panel so that the scale line on the knob aligns with the solution being tested
(3) Place the electrode in the solution to be tested, shake it slightly until the digital display stabilizes and read its pH value. After the measurement is completed, make a record.
Precautions before use:
(1) When using for the first time, due to the relatively dry electrode probe, it will affect the measurement accuracy of the instrument. Therefore, soak the electrode in a 3mol/L potassium chloride solution for 2 hours first.
(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. Dissolve the reagent completely to obtain a 3mol/L potassium chloride solution.
(3) Replace the electrode once a year (regardless of whether the electrode is functional or not).
calibration
We usually calibrate pH meters using the "two-point calibration method", which involves selecting two standard buffer solutions with pH=6.86 and pH=4.00 or pH=9.18.
For precision pH meters, in addition to "positioning" and "temperature compensation" adjustments, there is also an electrode "slope" adjustment. Firstly, perform "positioning" calibration with pH=6.86, and then select pH=4.00 (acidic) or pH=9.18 (alkaline) buffer solution for "slope" calibration based on the acidity and alkalinity of the test solution.
