Development and Validation of a GC-MS Method Based on Solid-Phase Extraction and Derivatization for Analysis of Free and Glucuronide-Conjugated Bisphenol F in Biological Samples

Background As one of the speculated bisphenols to replace bisphenol A (BPA), bisphenol F (BPF), naturally present in mustard, is structurally similar to BPA and may have similar estrogenic activity, but information on its toxicity is very limited compared to BPA.Objective In order to support the toxicology study of BPF at Heath Canada, a GC-MS method based on solid-phase extraction (SPE) and derivatization was developed for analysis of BPF in liver samples.Methods Samples were treated with beta-glucuronidase to convert BPF glucuronide to free BPF for analysis of total BPF.Results The method was validated for free BPF at different spiking levels, and recoveries ranged from 90-97.5% with RSDs from 0.11-5.54%. The method was also validated for glucuronide-conjugated BPF at different spiking levels of BPF mono-beta-D-glucuronide: recoveries ranged from 72.3-93.3% with RSDs from 1.7-8.94%. The method was used to analyze 60 liver tissue samples from rats dosed with BPF at different levels in a toxicology study. Free and glucuronide-conjugated BPF were not detected in any of the control samples, which were not dosed with BPF (average method detection limit: 0.31 ng/g) but detected in all the other liver tissue samples with levels increasing at higher doses. The percentage of glucuronide-conjugated BPF in total BPF varied among the liver samples, from as low as 9.8% to as high as 77.9%, indicating the importance of analyzing biological samples for BPF in both free and conjugated forms for total exposure.Conclusion A GC-MS method based on solid-phase extraction (SPE) and derivatization was developed for analysis of both free and glucuronide-conjugated BPF in liver samples. This method was validated not only for free BPF, but also for mono-beta-D-glucuronide-conjugated BPF for the first time to confirm the efficiency of the deconjugation procedure with enzyme.Highlights This method can be adapted and applied for analysis of free and glucuronide-conjugated BPF in other biological samples with appropriate validation in target sample matrixes.