Simultaneous Determination of Nine Perfluoroalkyl Carboxylic Acids in Chinese Wolfberry and Soybean by Gas Chromatography–Mass Spectrometry with a Novel Derivatization Method

Three novel derivatization reagents, tris(dimethylamino)methane, bis(dimethylamino)methoxymethane, and tert-butoxybis(dimethylamino)methane, were utilized for the simultaneous determination of nine perfluoroalkyl carboxylic acids (PFCAs) by gas chromatography-mass spectrometry (GC–MS). PFCAs were extracted from Chinese wolfberry and soybean by the extractant of ACN/water, and cleaned up on a WAX cartridge, then derivatized with 20 μL of derivatization reagent at 35 °C for 30 min, and finally analyzed by GC–MS. Several parameters, including the amount of derivatization reagents, derivatization temperature and time, as well as sample extraction and clean-up conditions, were optimized and the method was validated in Chinese wolfberry and soybean matrices. The proposed method showed low method quantification limits (MQLs) ranged from 0.25 to 0.40 ng/g and obtained matrix effect (|ME%|) ≤ 20%, which showed negligible matrix influence. The recoveries calculated at the spike levels ranged from 49.3 to 96.3% with relative standard deviations (RSDs) ranged from 1.2 to 14.7%. The proposed method based on a novel derivatization shows the advantages of fast and sensitive for the determination PFCAs in Chinese wolfberry and soybean.