Analysis of Steroid Estrogens in River Sediment by High Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry

Abstract

This paper describes analysis of steroid estrogens (estrone, estradiol, estriol, and 17α-ethynylestradiol) in river sediment using high performance liquid chromatography (Perkin Elmer FX15) electrospray ionization-mass spectrometry. River sediment samples were prepared by ultrasonic extraction with methanol-dichloromethane, followed by solid phase extraction involving C18 SPE cartridge (500 mg/6 cc). Dissolution was performed using ethyl acetate and methanol, and elution was performed with methanol in ethyl acetate (15 % v/v). The extracts were analyzed by HPLC–MS/MS in multiple reaction monitoring and negative modes with a Zorbax C18 column. Elution was carried out with a gradient of 0.2 % formic acid and methanol with 0.2 % formic acid. The recovery rates from river sediment samples ranged from 90 to 114 %, with relative standard deviations in the range 0.8–17 %. Limit of quantification was determined at 0.02 µg/L all the investigated steroid estrogens. Linear regression analysis was performed for concentrations ranging between 0.02 and 200 µg/L. Coefficient of determination values of more than 0.996 were obtained for all the standard solution calibrations. The method was successfully applied to identify the target analytes in river sediment collected from Langat River (Malaysia) at concentrations of microgram-per-gram in sediment.