Clean Chemistry for Elemental Impurities Analysis of Pharmaceuticals in Compliance with USP 232

United States Pharmacopeia updated its 100 years old metal analysis method with inductively coupled plasma mass spectrometry (ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES). These sensitive instruments require that sample preparation be at least as sophisticated as the instrumentation used in the analysis. Sample contamination during sample preparation has to be controlled to an acceptable level given the low detection limit of these instruments and the ubiquitous presence of elements. This article focused on sample contamination during sample preparation. Contaminations from environment, reagents, and lab apparatus were investigated for their impact on trace element analysis. Advice on clean lab practice was offered to the pharmaceutical industry in regard to contamination control in elemental analysis labs at a time when the industry is preparing for compliance with elemental impurities in drug products.