Method development for the extraction of six bisphenols in serum by LC-MS/MS

Bisphenols are a class of chemicals characterized by two phenol groups bonded to a carbon chain or other chemical groups. These chemical substances are applied in everyday products such as plastics, canned goods, thermal paper, and medical devices. Bisphenol A (BPA) is the most studied compound out of the bisphenol family, and exposure to BPA at low concentrations can induce endocrine-disrupting processes affecting the endocrine system and human reproductive capabilities. When two phenol groups react with acetone (CH3COCH3), Bisphenol A (-cetone) is formed. By reacting two phenol groups with other functional groups, such as formaldehyde (CH2O) and sulfonyl (SO2), other bisphenols like Bisphenol F (-ormaldehyde) and Bisphenol S (-ulfonyl) are synthesized. The regulation of BPA has led to its replacement with other bisphenol analogs, such as BPF and BPS, which can have similar negative impacts on human health. Therefore, it is interesting to develop a method for quantifying low concentrations of various bisphenols in biological samples. In this study, a preparation method was developed for the quantification of six bisphenols (BPs) in serum samples by LC-MS/MS. The six BPs of interest are: Bisphenol A (BPA; 4,4′-(propane-2,2-diyl)diphenol), Bisphenol AF (BPAF; 4,4′-(1,1,1,3,3,3-hexafluoropropane-2,2-diyl)diphenol), Bisphenol E (BPE; 4,4'-ethylidenebisphenol), Bisphenol F (BPF; 4-[(4-hydroxyphenyl)methyl]phenol), Bisphenol S (BPS; 4-(4-hydroxyphenyl)sulfonylphenol) and Bisphenol Z (BPZ; 4-[1-(4-hydroxyphenyl)cyclohexyl]phenol). The sample preparation method was developed to obtain optimal sensitivity and selectivity of the BPs. The sample preparation included solid-phase extraction (SPE) to improve separation, enhance sensitivity, and reduce potential interferences and matrix effects. The limit of quantification (LOQ) was found to be 2.1ng/mL for BPA, 0.1ng/mL for BPAF, 0.5ng/mL for BPE, 0.03ng/mL for BPF, 0.2ng/mL for BPS, and 0.2ng/mL for BPZ. Recovery testing was performed to evaluate the accuracy and correction of analyte loss during the extraction method. The robustness was evaluated by analyzing a pre-spiked serum sample with a fixed concentration of 500ng/mL multiple times (n=6) to evaluate the precision and variation in the measurements of the same sample. Lastly, the method was tested on real serum samples from Argentina. The conclusion is that further optimization is needed as the method is not sufficiently sensitive enough to quantify low concentra