Development of gas chromatography-tandem mass spectrometry detection method for 14 herbicides residues in milk

A gas chromatography-tandem mass spectrometry(GC-MS/MS) method for the simultaneous and rapid determination of 14 herbicides in milk was established. The samples were extracted with acetonitrile, cleaned-up with MgSO₄ and Na₂AC, filtered through 0.22 μm organic filter membrane, and the anlytes were determinated with GC-MS/MS (EI source and MRM mode). The results showed that the calibration curve was linear in the range of 0.005-1 mg/L and determination coefficient (R²) was higher than 0.990 2. The average recoveries of 14 herbicides were 76%-113% and the relative standard deviations (RSD) were 1.2%-8.6% (n=6) when the spiked levels were 0.01, 0.05 and 0.5 mg/kg. The limits of quantitation (LOQ) for 14 herbicides were 0.01 mg/kg. The method is accurate, sensitive, simple, and suitable for the simultaneous and rapid determination of 14 herbicides residues in milk.