Determination of Estrogens in Water Samples From Wastewater Treatment Plant Using Ultra-Performance Liquid Chromatography-Electrospray Tandem Mass Spectrometry Method

An instant estrogen screening and determination method,using the HLB solid-phase extraction and ultra-per-formance liqulid chromatography-electrospray tandem mass spectrometry (UPLC-MS/MS)in a multiple reaction monitoring (MRM)mode,was established for determination of seven estrogens(estradiol valerate,ethynylestradiol,estriol,estradiol,hexestrol,estrone and diethylstilbestrol) in the influent and final effluent of a wastewater treatment plant.Conditions for performances of soild-phase extraction(selection of extraction cartridge,eluate and its volume used for elution,pH adjustment of the water sample,and rinsing solution)and for UPLC-MS/MS analysis (mobile phase and gradient,capillary voltage,cone voltage,RF lens voltage,collision energy,ion source temperature,desolvation gas flow and cone gas flow)were optimized.In the case that all the seven estrogens were in the linear range of 1-100 μg·L^-1,in mass concentration,all the determination coefficients(r²)of the regression equation were over 0.9972,and the detection limit of the method ranged from 4.40 to 10.27 ng·L^-1 for estrogens.When the mass concentration of estrogens was raised to the range of 20-100ng·L^-1,the recovery rates of the target substances in the influent and effluent water samples were in the range from 70.3% to 95.1% and from 72.6% to 96.7%,separately,with relative standard deviation(RSD) below 10.4% and 9.5%,separately.This method was applied to determine estrogens in influents and effluents of four major integrated wastewater treatment plants in Nanjing.It was found that concentrations of estradiol valerate,estriol and estrone reached as high as dozens and even hundred of ng·L^-1 in the influenets and several or dozens in the final effluents.