Abstract: A sensitive gas chromatography-tandem mass spectrometric (GC-MS) method has been developed for simultaneous determination of alachlor, acetochlor and atrazine in feed samples. Three herbicides in feed were extracted and enriched efficiently by using the QuECheRS method.The extraction was separated by capillary column (HP-5MS , 30 m × 0. 25 mm ×0. 25 μm) and detected by GC/MS. The good linearities were obtained for 3 herbicides, and the linear range was 0 to 5 μg/ kg. The recoveries were 94.5% to 115. 4 % for the three herbicides, and the relative standard deviation (RSD) were 4.4 % to 9.2 %.The limit of detection(LOD) for the three herbicides were 1.5 μg/ kg. The method is suitable for quantitative and qualitative analysis of three herbicides in a sufficient number of samples with simplicity, sensitivity and repeatability, and which could meet the request of peptide antibiotic residue testing at home and abroad.

Key words: herbicides; GC/ MS; residue; cattle feed