Simultaneous measurement of urinary bisphenol A and alkylphenols by automated solid-phase extractive derivatization gas chromatography/mass spectrometry

Bisphenol A (BPA) and alkylphenols (APs) are widely used industrial chemicals. BPA is used to manufacture polycarbonate plastic and epoxy resins; APs are used to make alkylphenol ethoxylates, common nonionic surfactants. BPA and APs can leach into the environment during industrial production and after degradation of the polycarbonate plastics and nonionic surfactants. Environmental exposure to these phenolic compounds has been associated with adverse reproductive and developmental effects in wildlife. We developed a sensitive and robust method for measuring BPA and six APs; 3-tert-butylphenol, 4-tert-butylphenol, 4-n-octylphenol, 4-tert-octylphenol, 4-n-nonylphenol, and technical-grade nonylphenol in urine. The method is based on the use of automated solid-phase extraction (SPE) coupled to isotope dilution-gas chromatography/mass spectrometry (GC/MS). During the automated SPE process, the phenols are both extracted from the urine matrix and derivatized, using pentafluorobenzyl bromide, on commercially available styrene-divinylbenzene copolymer-based SPE cartridges. After elution from the SPE column, the derivatized phenols in the SPE eluate are analyzed by GC/MS. The method, validated on spiked pooled urine samples and on urine samples from exposed persons, has limits of detection of similar to0.1 ng in 1 mL of urine.