The chemical composition of pH standard buffer solutions have been defined by the U.S. National Bureau of Standards. Such solutions may be prepared by a competent chemist or technician. They are also available from most pH meter manufacturers. The following table lists the more popular pH standard solutions. For best accuracy, a pH meter should be standardized using a standard solution whose value is near that of the test solution.
Place electrodes in pH standard buffer solution.
Adjust pH meter temperature dial to the temperature of the standard solution. Remove electrodes from standard and rinse with water. Place electrodes in test solution. Adjust pH meter temperature dial to the temperature of the test solution. Read the pH of the test solution on the pH meter directly.