Simultaneous determination of 20 phthalate esters in oil-free food by UPLC/MS/MS

A quantitative method was established for the determination of 20 phthalate esters (PAEs) in oil-free food by ultra-performance LC/MS/MS and was used to evaluate the PAEs of 111 oil-free samples from supermarkets in Hangzhou City. By quantification with the internal standard D4-bis(2-ethylexyl) phthalate, linearity ranges of the 20 PAEs were observed with correlation coefficients of 0.9990-0.9999. For liquid and solid sample, the spiking recoveries were 65.5-129.9% with RSD of 2.7-9.7% and 70.9-126.9% with RSD of 1.6-9.8% (n = 6), and the method LODs were 0.05-7.4 microg/L and 0.6-14.4 microg/kg, respectively. Most of the 111 oil-free samples had detectable PAEs; the detection rate was 23.0-42.0%, and the concentration of PAEs was in the range of 1.0-38 610.9 microg/kg. The detection rate in the drink packaged in a glass bottle was the highest, next was laver, and the detection rate in the drink packaged in a plastic bottle was the lowest.