Determination of steroid sex hormones in water and urine matrices by stir bar sorptive extraction and liquid chromatography with diode array detection

Abstract

In this study, stir bar sorptive extraction and liquid desorption followed by high performance liquid chromatography with diode array detection (SBSE–LD–HPLC/DAD) were combined for the simultaneous determination of nine steroid sex hormones (estrone, 17α-estradiol, 17β-estradiol, 17α-ethynylestradiol, diethylstilbestrol, mestranol, progesterone, 19-norethisterone and norgestrel) in water and urine matrices. During the method development, it has been demonstrated that equilibrium time, ionic strength and back extraction solvents are the most important parameters to control, for determining the nine-hormones in water matrices, in which stir bars coated with 126 μl of polydimethylsiloxane were used. Assays performed on 30 ml water samples spiked at 10 μg/l levels under optimised experimental conditions, yielded recoveries ranging from 11.1 ± 4.9% (17β-estradiol) to 100.2 ± 10.4% (mestranol), showed that the methodology is well described by the octanol–water partition coefficients ( K PDMS/W ≈ K O/W) for the latter, while pronounced deviations to the theoretical efficiency ( K PDMS/W ≠ K O/W) were observed for the remaining hormones. From calibration studies, a good analytical performance for all hormones was attained, including a suitable precision (2.1–17.1%), low limits of detection (0.3–1.0 μg/l) and an excellent linear dynamic range (1.25–50.0 μg/l). Assays on environmental water and urine matrices showed recovery yields in worthy good agreement with the spiking level (10 μg/l), and suitability for profiling low μg/l levels of natural hormones in urine samples taken from pregnant women. The present methodology is easy, reliable and sensitive at the trace level, only requiring a low sample volume, showing to be a good analytical alternative to routine quality control for environmental and biomedical laboratories.