Liquid chromatography/multi-stage mass spectrometry of bisphenol A and its halogenated derivatives

Abstract

We report a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for analyzing bisphenol A (BPA) and its halogenated derivatives. Since only tetrachlorobisphenol A and tetrabromobisphenol A (TBBPA) are commercially available, mono-, di- and trichlorobisphenol A were synthesized and purified in order to be used as analytical standards. This family of compounds was studied using electrospray ionization and an ion trap mass analyzer in order to characterize the new compounds and to propose fragmentation pathways. Multi-stage mass spectrometry was used to confirm the genealogical relationship between the ions. Some product ions were traced from MS/MS to MS4 and the labelled compounds BPA-d16 and TBBPA-13C12 were used to assign some product ion structures. In general, the deprotonated molecule [M-H]- loses a methyl and/or a halogen group during both MS/MS and MS3, while the neutral loss of CO was also observed in MS3 spectra. We selected the most intense and characteristic MS/MS transitions for LC/MS/MS analysis. LC separation was performed in a reversed-phase column; methanol/water (no additives) was used as the mobile phase in gradient elution mode; and BPA-d16 was chosen as the internal standard. Solid-phase extraction (SPE) was used to pre-concentrate and to clean up water samples. The SPE LC/MS/MS method allows BPA and its halogenated derivatives to be detected at a few parts-per-billion (ppb) in surface water. Copyright © 2007 John Wiley & Sons, Ltd.