Direct aqueous injection LC−ESI-MS/MS analysis for the determination of 23 EU watch list substances in whole water samples.

The Watch List (WL) monitoring program in the European Union (EU) aims to identify and prioritize emerging pollutants in the aquatic environment that may pose risks to human health and the environment. Thus, reliable methods are needed to determine these substances. This study presents the development of a simple, fast, and green method for analysing 23 WL substances (4 antibiotics, 9 azole compounds, 6 other pesticides, and 4 sunscreens), covering a range of medium to very low polarity (log K ow 2.2–6.9), in whole environmental water samples using direct aqueous injection (DAI) in combination with liquid chromatography–electrospray ionization tandem mass spectrometry (LC–ESI-MS/MS). To process the samples, 0.5 mL of acetonitrile is added to 1 mL of raw water, followed by brief shaking. The mixture is then centrifuged to remove sedimented suspended solids before being injected into the LC instrument. A rigorous analytical greenness metric for sample preparation (AGREEprep) assigned this procedure a green score of 0.61. The method showed satisfactory performance characteristics for all analytes under investigation, including limits of quantification meeting the WL requirements, recoveries in the range of 79–120%, and intra-day precision with relative standard deviations in the range of 1.9–20%. The method is suitable for screening and monitoring purposes, as confirmed by the analysis of real samples. [Display omitted] • Analytes with a broad range of polarity (log K ow 2.2–6.9) were studied. • Whole water sample analysis performed combined with direct aqueous injection. • Sample preparation and analysis for 23 WL substances completed in 30 min. • Environmentally friendly method with a green score of 0.61 via AGREEprep. • DAI-LC–ESI-MS/MS analysis meeting all EU Watch List requirements. [ABSTRACT FROM AUTHOR]