Determination of 23 phthalic acid esters in food by liquid chromatography tandem mass spectrometry

•A rapid and sensitive method was developed for the determination of 23 phthalates in food samples.•Liquid samples were exacted by acetonitrile, while solid samples were prepared by QuEChERS or SPE.•The LODs were between 0.8 and 15μgkg−1 and LOQs were between 10 and 100μgkg−1.•With spiked concentrations, the recoveries were 75.5–115.2% and RSDs were 3.2–18.9%.•The DEHP was found in almost all samples. A rapid and sensitive method was developed for the determination of 23 phthalates in food samples including milk-based products, distilled liquor, wine, beverage, grain, meat, oil, biscuit (cookie), and canned food by liquid chromatography tandem mass spectrometry (LC–MS/MS). Liquid samples were exacted by acetonitrile, while solid samples were prepared by QuEChERS or glass-based SPE methods. The 23 phthalates were separated on Poroshell 120 EC-C18 column and followed by positive electrospray ionization as well as multi-reaction monitoring provided by a triple–quadrupole tandem mass spectrometer. To reduce contamination, the plastic materials were avoided in sample handling and preparation . The LODs were between 0.8 and 15μgkg−1 and LOQs were between 10 and 100μgkg−1. By using different concentrations: 100, 500, and 1000μgkg−1) for DINP and DIDP; 50, 100, and 1000μgkg−1 for other 21 phthalate compounds, the spiked recoveries were within 75.5–115.2% and the relative standard deviations (RSDs) were in the range of 3.2–18.9%. The proposed protocol was then applied to the analysis of 623 real samples collected from the two sides of the Taiwan Straits, and the DEHP was found in almost all samples tested in this study, with levels ranging from 0.02 to 2685mgkg−1. The present study demonstrated a rapid, sensitive, and accurate method for determining 23 phthalates in foodstuffs.