Simultaneous Determination of Phenolic Endocrine Disruptors in Water Samples by Poly(sodium 4-styrenesulfonate) Modified CE Coupled with Hollow-Fiber Liquid-Phase Microextraction

A CE combined with amperometric detection method has been developed for simultaneous determination of nine environmental endocrine disruptors, including bisphenol A, methylparaben, ethylparaben, propylparaben, 4-tert-butylphenol, diethylstilbestrol, 17 alpha-ethinylestradiol, beta-estradiol and estriol. In this work, various experimental parameters affecting enrichment factors, electrophoretic separation and detection were investigated in detail. And poly(sodium 4-styrenesulfonate) was selected as the buffer modifier, resulting in considerable improvement of the resolution of the target analytes. Under the optimum conditions, nine analytes could be well separated within 30 min in a 10 g/L poly(sodium 4-styrenesulfonate) modified 60 mmol/L Na2B4O7-H3BO3 buffer (pH 7.60). For each analyte good linear correlation between electrochemical response and its concentration at two or three grades was obtained, the method detection limits reached 0.047-13 ng/mL (S/N = 3) with the assistance of hollow-fiber liquid-phase microextraction, and the highest enrichment factor was up to 255-fold. This proposed method has been applied for the direct analyses of real environmental water and tap water samples without need of derivatization, the average recoveries were in the range of 81.4-117 %, and the corresponding relative standard deviations were lower than 6.2 %.