All of the following Reference Standard Buffer solutions are compared against and certified traceable to National Institute of Standards and Technology (NIST) Standard Reference Materials. Exact reference materials used are shown on the product labels. Accurate to ±0.01 pH of indicated value at 25°C. For most routine pH measurements, a two-point standardization of a pH meter should be used; pH 4 and 7 buffers can be used for pH measurement of samples of pH 7 or below, while pH 7 and 10 buffers can be used for pH measurement of samples of pH 7 or higher. Other combinations of pH buffers may also be used, depending on the capability of the pH meter being used. For increased accuracy, buffers with pH values closer to that of the sample being measured can be used.
