Ultrasound-assisted emulsification microextraction followed by gas chromatography-mass spectrometry and gas chromatography-tandem mass spectrometry for the analysis of UV filters in water

A methodology based on ultrasound-assisted emulsification microextraction (USAEME) has been developed for the simultaneous analysis of ten UV filters (2-ethylhexyl methoxycinnamate (2EHMC), 4- methylbencylidene camphor (4MBC), benzyl salicylate (BS), ethylhexyl dimethyl PABA (EHPABA), ethylhexyl salicylate (EHS), etocrylene (Eto), homosalate (HMS), isoamyl methoxycinnamate (IAMC), menthyl anthranilate (MA) and octocrylene (OCR)) in different water samples employing two detection modes, gas chromatography-mass spectrometry (GC-MS), and gas chromatography-tandem mass spectrometry (GC-MS/MS). The extraction parameters such as the extraction solvent, the temperature and the time of extraction, and the addition of salt were optimized by means of experimental design tools. Selected conditions were 100 μL of chloroform, 10 mL of sample, 2 g of salt (NaCl) and 5 min of extraction. Good linearity (R2 > 0.9910), quantitative recoveries (> 90% for most of compounds) and satisfactory precision (RSD < 10% in most cases) were achieved under the optimal conditions. The methodology was successfully applied to the analysis of different types of water samples including seawater, spas, rivers, swimming pools, and aquaparks, in which most of the target compounds were found at concentrations sometimes over the part per million. Since no significant matrix effect has been found for any of the water types analyzed, quantification could be carried out by using conventional external calibration, thereby allowing a high analytical throughput and a valuable protocol simplification.