The pH 7.0 calibration solution is used to calibrate pH meters in laboratory environments. It consists of disodium hydrogen phosphate, citric acid and sodium azide.

During calibration, the electrode potential of the pH meter is corrected using the known pH value of the calibration solution to provide an accurate measurement. This process ensures that the meter provides accurate and consistent measurements at different pH values. Accurate measurement of pH is essential in many scientific and industrial fields, including pharmaceuticals, biotechnology, food industry and environmental analysis.