超高效液相色谱-串联质谱法分析乙螨唑在柑桔和土壤中的残留消解动态

应用超高效液相色谱-串联质谱(UPLC-MS/MS)建立了乙螨唑在柑桔和土壤中残留的分析方法,并研究了田间试验条件下乙螨唑在柑桔和土壤中的消解动态。样品采用乙腈提取,硅胶柱净化,UPLC-MS/MS检测,外标法(ESTD)定量。在0.002 ~1 mg/L质量浓度范围内,乙螨唑的仪器响应值与质量浓度呈良好线性关系,相关系数为0.998 9。该方法的最小检出量为6.0×10-6 μg,乙螨唑在柑桔和土壤中的最低检测浓度均为0.002 mg/kg。当乙螨唑在柑桔和土壤中的添加水平为0.002 ~1 mg/kg时,平均回收率为87.3% ~98.4%,相对标准偏差在5.5% ~8.6%之间。消解动态试验表明,乙螨唑的消解动态曲线符合一级动力学方程,在柑桔和土壤中的半衰期分别为5.6 ~7.6 d 和 5.3 ~8.6 d。

Residue Decline Dynamics of Etoxazole in Orange and Soil by UPLC-MS/MS

A rapid,accurate and sensitive method has been developed to determine etoxazole residues in orange and soil by UPLC-MS/MS.The decline dynamics of etoxazole residues in orange and soil were studied under the conditon of field experiment.The samples were extracted by acetonitrile,followed by clean-up on silica gel cartridge and analyzed by UPLC-MS/MS.External reference method was used for quantitative determination.The linearity was satisfied (r=0.998 9) in the concentration range of 0.002-1 mg/L.The limit of detection was 6.0×10~(-6) μg,and the limit of quantification in orange and soil was 0.002 mg /kg.The average fortified recoveries varied from 87.3% to 98.4% with the coefficient of variation of 5.5%- 8.6%.The study of residue dynamics indicated that the curve of decline accorded with the first-order kinetics equation,and the half-life of etoxazole in orange and soil were 5.6- 7.6 d and 5.3- 8.6 d,respectively.