Abstract:In this study, a new and reliable analytical method was established for the evaluation of 14 kinds of acidic herbicides residues in livestock meat through optimizing the pH value of the extraction solution, dispersing solid-phase extractant and concentrated sulfuric acid-methanol solution, in combination with gas chromatography-mass spectrometry (GC-MS). The samples were extracted by acetonitrile, the pH of the extraction solution was adjusted to ≤ 3, the fat was removed by n-hexane saturated with acetonitrile, and purified by dispersed solid-phase extractor C18, dried with nitrogen, derivatized by adding concentrated sulfuric acid-methanol solution for 2 min, extracted with n-hexane, t purified by saturated sodium chloride solvent, and determined by EI source-gas chromatography -mass spectrometry and the matrix external standard method. The results showed that the 14 kinds of acid herbicides displayed a good linearity in the concentration range of 0.01~0.5 μg/mL, with all the correlation coefficients being greater than 0.999, the limit of detection in the range of 0.001~0.003 mg/kg and the limit of quantification in the range of 0.003~0.01 mg/kg. At the spiking levels (0.01, 0.05, 0.1 mg/kg), the average recoveries of blank samples were in the range of 88.21%~110.0%, with the relative standard deviations (n=6) ranging between 1.02% and 8.32%. The advantages of this method include short derivatization time, less consumption of pretreatment reagents, convenient method and high sensitivity, which can be used for the determination of 14 kinds of acidic herbicides residues in livestock meat.
