Use of solid-phase microextraction followed by on-column silylation for determining chlorinated bisphenol A in human plasma by gas chromatography-mass spectrometry

In this study, a solid-phase microextraction (SPME) method based on poly(acrylate)-coated fibres has been developed for detection and quantification of chlorinated bisphenol A in human plasma due to the need for an assessment of human exposure to them. After desorption of the analytes for 7 min at 300 °C, they were directly derivatized in the GC injector port by injection of 2 μL of diluted bis(trimethylsilyl)trifluoroacetamide (BSTFA). The formation of trimethylsilylate derivatives improves the selectivity, sensitivity and performance of the chromatographic properties obtained when the analytes are directly separated. Quantification was carried out using single-ion monitoring (SIM). The respective chloroderivative molecular ions appear at 406, 440, 474 and 508 m/z; whereas the base peaks corresponding to a loss of a methyl group in all cases appear at 391, 425, 459 and 493 m/z for mono-, di-, tri- and tetrabisphenol A, respectively. Deuterated bisphenol A (BPA-d16) was used as an internal standard. The method was applied to the determination of Cl-BPA, Cl2-BPA, Cl3-BPA and Cl4-BPA at very low concentration levels in plasma. Recovery efficiencies were close to 100% in all cases.