Fast determination of perfluorocompounds in packaging by focused ultrasound solid–liquid extraction and liquid chromatography coupled to quadrupole-time of flight mass spectrometry

A focused ultrasound solid–liquid extraction (FUSLE) and liquid chromatography (HPLC) coupled to quadrupole-time of flight mass spectrometry (QTOF-MS/MS) based method is proposed to determine six perfluorocarboxylic acids (PFCA) and perfluorooctane sulfonate (PFOS) in food-contact packaging. FUSLE, a simple, inexpensive and fast extraction technique, has been carried out with just 8 mL of ethanol in one cycle of only 10 s. The whole method presented good repeatability and intermediate precision, with RSDs below 11% and 15%, respectively; limits of detection, with values between 0.5 ng/g and 2.2 ng/g, and successful recovery values, around 100% in all cases. The developed method has been validated and applied to the analysis of real food-contact packaging samples. FUSLE results have been compared to those obtained with pressurized liquid extraction (PLE) and no significant differences between them have been found. PFAA were detected in all the packaging samples analyzed, in a concentration range between 4 ng/g and 29 ng/g, being PFHpA (perfluoroheptanoic acid) the most abundant of them.