Determination of Polychlorinated Biphenyls and Phthalate Esters in Milk Powders by GC-MS/MS with Solid Phase Extraction

A method of gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) with solid phase extraction purification was developed for detecting 15 polychlorinated biphenyls (PCBs) and 16 phthalate esters (PAEs) residues in milk powders. The extraction conditions, purification methods and conditions of the samples were optimized. The samples were extracted with acetonitrile, cleaned up with solid phase extraction, detected by GCMS/MS under multiple reaction monitoring (MRM) mode, and quantified using external standard. The results showed that the calibration curves of PCBs and PAEs had good linear relationship in the range of 51 000 μg/L and 31 000 μg/L, respectively, with the correlation coefficients (r2) not less than 0992 2. The limits of detection (LODs) of PCBs and PAEs were 0530 μg/kg and 0310 μg/kg, and the limits of quantification (LOQs) were 1580 μg/kg and 1030 μg/kg, respectively. The average recoveries of the spiked samples were 724%948% for PCBs and 824%1071% for PAEs with RSD (n=6) less than 9.1%. This method is simple pretreatment, high sensitivity and high accuracy, PCBs and PAEs can be detected simultaneously, which can be used for daily detection of PCBs and PAEs in laboratory.