The pH of a solution is the most common routinely performed measurement in a molecular biology laboratory. As the pH of any solution affects all chemical and biochemical reactions, it is very important to have a reliable and accurate measurement of it. The pH-meters are used to measure the pH of any solution. It functions by measuring the voltage developed between two electrodes immersed in the sample and compare that value to a calibration derived from the same electrode pair and known standards. These standard buffer solutions must be accurate and reliable and are used for pH meter calibration. A properly calibrated pH meter gives more precise and accurate readings.
Buffer Solution pH 7.0 (± 0.02) is used as a standard buffer in Molecular Biology as a calibration buffer for the pH meters. A buffer solution is one which resists changes in pH when small quantities of an acid or an alkali are added to it. It is an neutral buffer solution