THE USE OF STANDARD REFERENCE MATERIALS IN SPECTROMETRIC AND ELECTROANALYTICAL QUALITY ASSURANCE PROGRAMS

To ensure that a chemical measurement process yields accurate results, well-characterized materials such as standard reference materials (SRMs) should be used. SRMs, which are characterized for their chemical composition, fall into two general categories: those used as primary calibration materials and those used as control materials. SRMs intended to be used as calibration materials include primary chemicals such as potassium dichromate and benzoic acid, pH buffers, spectrometric standard solutions, and some of the metal SRMs. Control materials are chemical matrix materials such as bovine liver, citrus leaves, river sediment, and coal. The use of SRMs is discussed with reference to these categories in the context of quality assurance in both spectrochemical and electrochemical analysis programs. Guidelines on how to choose the appropriate material for a given situation are presented, and some problems associated with making inappropriate choices are discussed. © 1992.