Comprehensive In Vitro Metabolism Study of Bisphenol A Using Liquid Chromatography-High Resolution Tandem Mass Spectrometry

Bisphenol A (BPA) metabolism has been investigated using several in vitro models, including human and rat liver microsomes and subcellular (S9) fractions, as well as human-recombinant cytochrome P450 3A4 (CYP3A4) expressed in Supersomes, for a comprehensive look at all possible metabolic pathways. By an untargeted approach using liquid chromatography coupled to a high-resolution quadrupole-time-of-flight mass spectrometer, we were able to detect a large number of known Phase I and Phase II metabolites of BPA, as well as several previously uncharacterized ones. A detailed fragmentation study of BPA and its detected metabolites was crucial to confirm structures. Isotope-labeled BPA analogs were highly useful for the structural elucidation of many metabolites. These results contribute to a better understanding of BPA metabolism, including pathways that may introduce additional toxicity, as well as help with the assessment of BPA exposure in different biological matrices.