Simultaneous determination of PAHs and pesticides in milk based on improved QuEChERS combined with GC-MS/MS

A simultaneous detection technique for 16 polycyclic aromatic hydrocarbons (PAHs) and 133 pesticides in milk was developed using QuEChERS combined with GC-MS/MS. The samples were extracted and salted with 1 % acetic acid acetonitrile, and the optimum amount of clean-up sorbent was optimized by Box-Behnken design. The targets were separated on an HP-5MS column (30 m×0.25 mm×0.25 μm), detected in multiple reaction monitoring (MRM) modes, and quantified by external standard method with a matrix-matched standard curve. The results showed that the 149 targets showed good linearity (R²>0.997) in the corresponding ranges, and the limits of detection (LOD) and limits of quantification (LOQ) were in the ranges of 0.003–1.67 μg/kg and 0.01–5 μg/kg, respectively. The average recoveries ranged from 72.40 % to 118.49 % at three spiked levels of 1, 2, and 10 times LOQ, and the relative standard deviations (RSDs) of Intra-RSD and Inter-RSD were 0.12∼15.09 % and 0.07∼16.04 %, respectively. The method is easy and quick to operate, with high sensitivity, good recovery, and precision, which can help to identify potential sources of contamination in the environment and provide a quick and easy method for the regulation of milk.