Standard method and operating procedures for preparing pH meter calibration solutions
The pH meter should be regularly calibrated to ensure that its precision and accuracy meet the requirements. How to calibrate a pH meter, or in other words, how to calibrate an acidity meter. The following is the information compiled by the author. Let's take a look at the calibration solution and method of the pH meter and learn about them together.
Standard method for preparing pH meter calibration solution
1. PH4 potassium hydrogen phthalate standard buffer solution:
Accurately weigh 10.12g of potassium hydrogen phthalate [KHC8H4O4] dried at 115 ± 5 ℃ for 2-3 hours, dissolve and dilute to 1000ml with water.
2. PH7 phosphate standard buffer solution (pH7.4:
Accurately weigh 4.303g of anhydrous disodium hydrogen phosphate and 1.179g of potassium dihydrogen phosphate dried at 115 ± 5 ℃ for 2-3 hours, dissolve and dilute to 1000ml with water.
Additional information: Phosphate standard buffer solution (pH 6.8), accurately weigh 3.533g of anhydrous disodium hydrogen phosphate and 3.387g of potassium dihydrogen phosphate dried at 115 ± 5 ℃ for 2-3 hours, add water to dissolve and dilute to 1000ml.
3. PH9 borax standard buffer solution:
Accurately weigh 3.80g of borax [Na2B4O7 · 10H2O] (note: avoid weathering, dissolve and dilute to 1000ml with water, place in a polyethylene plastic bottle, seal tightly, and avoid contact with carbon dioxide in the air).
A pH meter is used to measure the pH value of a solution using the potentiometric method. Therefore, the working mode of a pH meter is not only to measure the pH value of the solution, but also to measure the electromotive force of the battery. PH, in Latin, is the abbreviation for Pondus hydrogeni, which is the activity of hydrogen ions in a substance. PH is the negative logarithm of the concentration of hydrogen ions.
