Trace Analysis of Potentially Mutagenic Boronic Acids and Esters in Drug Substance by ICP-MS

Boronic acids and boronate esters are commonly used reagents in Suzuki–Miyaura coupling chemistry which are known to be weakly mutagenic in microbial assays. In this paper, we describe an inductively coupled plasma mass spectrometer method (ICP-MS) for the analysis of boron at low parts per million levels. Boronic acid and ester levels are then calculated stoichiometrically in a drug substance based on the determination of boron with good sensitivity (LOQ of 0.8 ppm). The paper outlines some of the important aspects of the method and instrument features such as use of organic diluent, spray chamber configuration, and its optimization which are critical for analysis of trace inorganic species in drug substances.