Measurement of bisphenol A levels in human urine

We report a new approach for assessing human exposure to bisphenol A (BPA) by measuring BPA in urine after enzymatic deglucuronidation. This method in volves addition of C-13(12)-labeled BPA, enzymatic deconjugation, solid-pha se extraction, and derivatization with pentafluorobenzyl bromide. The produ ct of the derivatization is separated by gas chromatography followed by mas s spectrometric detection using negative chemical ionization and selected i on monitoring. Using this analysis method, urine samples fortified with bot h a constant level of labeled BPA and a range of unlabeled BPA levels (0.27 -10.6 ng/ml) demonstrated constant percentage recovery. In addition, a rang e of urine sample volumes (0.25-10.0 ml) with constant amounts of added int ernal standard produced a linear response (r(2)=0.99). The method limit of detection was 0.12 ng/ml. This method was validated by duplicate analyses u sing gas chromatography coupled to a high-resolution mass spectrometer.