Determination of benzophenone-UV filters in human milk samples using ultrasound-assisted extraction and clean-up with dispersive sorbents followed by UHPLC–MS/MS analysis

A new sample preparation method for the determination of five benzophenone UV-filters in human breast milk has been developed. The procedure involves the lyophilization of the sample, and its subsequent extraction by ultrasound sonication using acetonitrile. In order to reduce matrix effects produced by milk components that are coextracted, mainly proteins, sugars and lipids, a further clean-up step with a mixture of dispersive-SPE sorbents, C18 and PSA, was applied. Extraction parameters were optimized using experimental design, and the compounds were detected and quantified by ultrahigh performance liquid–chromatography tandem mass spectrometry (UHPLC–MS/MS) in positive ESI mode. Analytes were separated in 10min. BP-d10 was used as internal standard. The limits of detection (LODs) were between 0.1 and 0.2ngmL−1, and the limits of quantification (LOQs) were between 0.3 and 0.6ngmL−1 for the target analytes. The inter- and intra-day variability was