Determination of Bisphenol A, Nonylphenol and Octylphenol in Animal Food by Isotopic Dilution Liquid Chromatography-Tandem Mass Spectrometry

A comprehensive analytical method based on ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been developed for the simultaneous determination of bisphenol A, nonylphenol and octylphenol in meat, egg, infant formula and milk. In this study, solid phase extraction (SPE) and gel permeation chromatography (GPC) were compared and the background contaminations of the target compounds from the pretreatment procedure were studied. Samples were extracted by ethyl acetate: cyclohexane (1:1, V/V) and purified by GPC. Satisfactory linearity (R-2>0.999) was obtained over the range of 0.25-1600 mu g/L, with limits of quantification (LOQ) of 0.2 mu g/kg in meat and egg, and 0.4 mu g/kg in infant formula. Mean recoveries of three target compounds (spiked at three concentration levels) ranged from 85.9%-117.0%, with relative standard deviations (RSD) less than 20%. The method was applied in the analysis of meat, egg, infant formula and milk taken from Beijing. As a result, nonylphenol presented a highest detectable frequency, in the range of 0.27-1357 mu g/kg. In addition, bisphenol A was also detected in this survey.