Sensitive analysis of steroid estrogens and bisphenol a in small volumes of water using isotope-dilution ultra-performance liquid chromatography-tandem mass spectrometry

An isotope-dilution ultra-performance liquid chromatography electrospray tandem mass spectrometry method combined with dansylation was established to sensitively quantify four steroid estrogens (estrone, 17 alpha-estradiol, 17 beta-estradiol and 17 alpha-ethynylestradiol) and bisphenol A in sewage influent and effluent. A simple hexane extraction was performed from a small volume (10 mL), followed by dansyl chloride derivatization and purification with a silica cartridge. The method effectively reduced the matrix effects in sample extract and permitted the selective and sensitive determination of target compounds from complicated matrices. The detection limits of the method for steroid estrogens were 0.20 -0.90 ng L-1 in influent and 0.10-0.20 ng L-1 in effluent samples. For bisphenol A, the limits detection of the method were 20 and 0.80 for influent and effluent samples, respectively. Recoveries of 85%-96% were observed in all matrices. The method was applied to analyze residual estrogens and bisphenol A in sewage influent and effluent samples from Beijing, China. The concentrations of bisphenol A (636 1200 ng L-1) were up to 250 times higher than those of steroid estrogens. Estrone was the dominant estrogen in influent and effluent samples, while similar concentrations of 17a-estradiol and 17 beta-estradiol were detected in all samples. (C) 2018 Elsevier Ltd. All rights reserved.