Determination of oestrogen hormones in raw and treated water samples by reverse phase ultra-fast liquid chromatography mass spectrometry – a case study in Johannesburg South, South Africa

Abstract

Hormones in water samples have been classified as ‘emerging pollutants’ and may pose a potential risk for humans. Hormones can be found in both surface and ground water at low concentrations. These compounds enter water streams through wastewater treatment plants (WWTP) and may elicit endocrine disruption to organisms. As a result of the low concentrations, a suitable analytical methodology is essential for their determination. In the past, residues of oestrogens in aqueous and solid environmental samples have commonly been analysed by gas chromatography (GC) equipped with mass spectrometry (MS). However, the necessary derivatisation steps are not only time consuming and laborious but also tedious. The first part of this case study was to develop a method to determine trace concentrations of the estrone (E1), 17α-estradiol (E2α), 17-β-estradiol (E2β) and 17-α-ethinylestradiol (EE2) hormones using reverse phase ultra-fast liquid chromatography mass spectrometry (RP-UFLC). Using the developed method, the second part of the case study was to determine the concentrations of the hormones in raw and treated potable water samples from the Vaal River catchment area in the south of Johannesburg, South Africa. Analytes were extracted by solid phase extraction (SPE C₁₈ sorbent) cartridges and subsequently injected into ultra-fast liquid chromatography with the reverse phase column coupled to mass spectrometry (UFLC-MS) for analyte determinations. The limits of quantification were in the range of 0.24 to 0.32 ng·L^-1 for the analytes. Accuracy was 95.6, 93.8, 97.6 and 100.9% for EE2, E2α, E2β and E1, respectively. In raw water samples taken during the rainy wet season, estrone was detected at concentrations of 0.90 and 4.43 ng·L^-1. However, treated potable water samples did not contain detectable levels of hormones. This is potentially due to the ability of a water treatment process to remove endocrine disruptors during water purification.