Salting-out assisted liquid-liquid extraction combined with LC-MS/MS for the simultaneous determination of seven organic UV filters in environmental water samples: method development and application

Organic UV filters (OUVFs), the active ingredient in sunscreens, are of environmental concern due to reported ecotoxicological effects in aquatic biota. Determining the environmental concentrations of these chemicals is essential for understanding their fate and potential environmental risk. Salting-out assisted liquid-liquid extraction (SALLE) coupled with liquid-chromatography tandem mass spectrometry (LC-MS/MS) was developed for simultaneous extraction, separation, and quantification of seven OUVFs (2,4-dihydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 4-methylbenzylidene camphor, butyl-methoxy-dibenzoyl methane, octocrylene, octyl methoxycinnamate, and oxybenzone). Method detection limits (MDLs) ranged from 11 to 45 ng/L and practical quantification limits (PQLs) from 33 to 135 ng/L. Method trueness, evaluated in terms of recovery, was 69-127%. Interday and intra-day variability was <6% RSD. The coefficients of determination were > 0.97. The method was applied to river and seawater samples collected at 19 sites in and near Port Phillip Bay, Australia, and temporal variation in OUVF concentrations was studied at two sites. Concentrations of OUVF were detected at 10 sites; concentrations of individual OUVFs were 51-7968 ng/L, and the maximum total OUVF concentration detected at a site was 8431 ng/L. Recreational activity and water residence time at the site contributed to OUVF's environmental presence and persistence. The benefits of the SALLE-LC-MS/MS method include its simple operation, good selectivity, precision over a wide linear range, and that obtained extracts can be directly injected into the LC-MS/MS, overall making it an attractive method for the determination of these OUVFs in environmental water matrices. To our knowledge, this is the first report of the occurrence of OUVFs in Port Phillip Bay, Australia.

Automated summary

This study developed a SALLE-LC-MS/MS method for simultaneous extraction, separation, and quantification of organic UV filters (OUVFs) in water. The presence of OUVFs in river and seawater samples collected in and near Port Phillip Bay, Australia was investigated. The concentrations of OUVFs varied over time and were influenced by recreational activities and water residence time.