Trace analysis of estrogenic compounds in surface and groundwater by ultra high performance liquid chromatography-tandem mass spectrometry as pyridine-3-sulfonyl derivatives

Natural estrogens (estrone: E1, 17β-estradiol: E2, estriol: E3) and synthetic 17α-ethynylestradiol (EE2) are reported as strong endocrine disruptors even at extremely low concentrations. Therefore, the watch list from the European Commission regarding emerging aquatic pollutants recommended maximum detection limits of 0.035 ng/L for EE2 and 0.4 ng/L for E1 and E2. In this study, a UHPLC-ESI-MS/MS method allowing quantification of E1, E2, E3 and EE2 in aqueous matrices was developed. The analytes were derivatized using pyridine-3-sulfonyl chloride and a broad range of product ions were generated and their specificity was assessed by analyzing both surface and groundwater. At least two product ions for each estrogenic compound were proved to be specific and hence suitable for quantification and confirmation. In complex aqueous matrices, analyte responses were particularly affected by ion suppression. This phenomenon was reduced by optimizing the clean-up and selecting a suitable stationary phase for the chromatographic separation. The limits of quantification assessed in surface water with the optimized method ranged from 0.098 ng/L (EE2) to 2.73 ng/L (E3).