Determination of phthalic acid esters in drinking water and olive oil by ultra-high performance liquid chromatography-electrospray-tandem mass spectrometry: Study of phthalate migration from plastic bottles to drinking water at different domestic exposure conditions

Abstract

A UHPLC-ESI-MS/MS method for the determination of ten phthalates in mineral water and olive oil samples was developed. A hold-back column placed between pump and injection valve allowed preventing phthalate instrumental background contamination. Good instrumental limits of detection (1-9 µg/L), precisions (RSD <23.9%), and trueness (relative error <20%) were achieved. A migration study from PET bottles into mineral water at different domestic exposure conditions revealed than only diethyl phthalate migrated when exposed at 40 oC although at not-quantified levels up to six months of exposure. No matrix effect was present for mineral waters and only dicyclohexyl phthalate was detected. Matrix-matched calibration was proposed for the analysis of olive oils due to the huge matrix-effect encountered with the employed liquid-liquid extraction method. Among the multiple positives detected in olive oil samples, only dibutyl phthalate was found in one sample at the established EU specific migration level (0.3 mg/kg).