Determination of 11 kinds of pesticide residues in liquid milk by dispersive solid phase extraction coupled with ultra performance liquid chromatography-tandem mass spectrometry

Abstract

Objective： This study aimed to evaluate the safety of pesticide residues in liquid milk. Methods： A method for simultaneous determination of 11 kinds of pesticide residues by ultra-high-performance liquid chromatography-tandem mass spectrometry was established. The samples were extracted by acetonitrile, purified by C18 and PSA solid phase extractants, separated on a column Xbridge BEH C18 (100 mm×2.1 mm, 1.7 μm), determined in multi-reaction monitoring mode, and optimized for pre-treatment parameters using response surface method. Results： The optimal conditions for pretreatment were 10 mL acetonitrile, 50 mg C18 and 30 mg PSA. The linear relationships of 11 kinds of pesticides were good in the concentration range of 1.0~100.0 μg/L, and the correlation coefficients (R2) were all ＞ 0.999. With addition of 10, 20, 100 μg/kg, the average recoveries were 82.7%~102.0%, the relative standard deviations were 2.89% to 8.87%, and the limits of detection (LOD) and limits of quantitation (LOQ) were 2.0~3.0 μg/kg and 5.0~10.0 μg/kg, respectively. Conclusion： The method is simple, convenient, rapid, high recovery rate and high reproducibility, which could accurately determine 11 kinds of pesticide residues in liquid milk.

Keywords

• dispersive solid phase extraction
• uplc-ms/ms
• liquid milk
• pesticide residue