Multiresidue analysis of 20 herbicides in soil and water by gas chromatography-mass spectrometry

A rapid multiresidue method has been developed for the simultaneous analysis of 20 herbicides in soil and water by gas chromatography-mass spectrometry (GC-MS).Residues were extracted from soil with acetonitrile,purified by solid phase extraction (SPE),eluted by V(petroleum ether):V(ethyl acetate)=9:1 and then concentrated to a small volume with acetone before GC-MS analysis.The target compounds in water were extracted with C18 SPE and eluted by V(methanol):V(ethyl acetate)=1:1.The average recoveries of 20 herbicides ranged from 72%-109% in soil with relative standard deviations (RSDs) 0.15%-16.5% and 77%-113% in water with the RSDs 0.45%-16.3%,respectively.The limits of quantification (LOQs) were 0.01 mg/kg in soil and 0.1 μg/L,respectively.The results indicated that the developed method is sensitive,reproducible and has good cleanup effect.