Dispersive liquid-liquid microextraction followed by gas chromatography-mass spectrometry for the rapid and sensitive determination of UV filters in environmental water samples

The performance of the dispersive liquid-liquid microextraction (DLLME) technique for the determination of eight UV filters and a structurally related personal care species, benzyl salicylate (BzS), in environmental water samples is evaluated. After extraction, analytes were determined by gas chromatography combined with mass spectrometry detection (GC-MS). Parameters potentially affecting the performance of the sample preparation method (sample pH, ionic strength, type and volume of dispersant and extractant solvents) were systematically investigated using both multi- and univariant optimization strategies. Under final working conditions, analytes were extracted from 10 mL water samples by addition of 1 mL of acetone (dispersant) containing 60 mu L of chlorobenzene (extractant), without modifying either the pH or the ionic strength of the sample. Limits of quantification (LOQs) between 2 and 14 ng L-1, inter-day variability (evaluated with relative standard deviations, RSDs) from 9% to 14% and good linearity up to concentrations of 10,000 ng L-1 were obtained. Moreover, the efficiency of the extraction was scarcely affected by the type of water sample. With the only exception of 2-ethylhexyl-p-dimethylaminobenzoate (EHPABA), compounds were found in environmental water samples at concentrations between 6 +/- 1 ng L-1 and 26 +/- 2 ng mL(-1).