Residual Decline of Carbendazim in Ginseng and Soil by Liquid Chromatography-Tandem Mass Spectrometry

Liquid chromatography-tandem mass spectrometry(LC-MS/MS)was used to study the residual decline and final residues of carbendazim in ginseng and soil.The method had a good linear correlation(r≥0.9985)in the range of 0.01-0.5μg/mL.The recoveries of carbendazim at spiked level of 0.01-0.2μg/kg were in the range of 82.74%-91.88% with relative standard deviations of 2.85%-6.28%.The minimum detection concentration was 0.005 mg/kg.The results of field trial showed that when the sprayed dose was 52 500 g a.i./hm2,the half-lives were 11.6-13.7dand 10.4-13.0din ginseng and soil,respectively,and the residues of carbendazim were 0.0075-0.0332mg/kg and 0.0068-0.0428mg/kg.When the most sprayed dosage were 52 500 g a.i./hm2,the maximum residue limit(MRL)of carbendazim may be suggested to be 0.5mg/kg,and the preharvest interval of carbendazim should be set at 28 d.