Potassium bitartrate for pharmaceutical use must comply with USP requirements. The actual monograph (USP 42) uses a colorimetric method for the determination of ammonium impurities. Ion chromatography allows the measurement in a single determination under the same conditions used for the potassium assay (see AN-C-181). In the course of the USP monograph modernization, this ion chromatographic approach makes this type of analysis even easier.
