茚虫威对映体在番茄、葡萄及水中的液相色谱-串联质谱检测方法

建立了反相条件下茚虫威在对映体水平上的液相色谱-串联质谱(LC-MS/MS)残留分析方法。采用基质匹配标准品的外标法定量,比较分析了基质分散萃取与固相萃取2种净化方法中基质效应的影响。番茄和葡萄样品均采用乙腈提取,NH2/Carb复合固相萃取小柱净化;水样直接采用C18-H固相萃取小柱富集净化。手性拆分的色谱条件为:Chiralpak AD-RH手性分离柱,以V(乙腈)∶V(水)=65∶35为流动相,柱温25 ℃,流速0.4 mL/min。结果表明:在0.005~0.5 mg/kg(水样为mg/L)添加水平范围内,茚虫威对映体在3种基质中的回收率在65.5% ~117.0%之间,相对标准偏差(RSD,n=5)为4.1% ~18.1%。对映体的检出限(LOD)为1.4~4.3 μg/kg(μg/L),定量限(LOQ)为4.7~14.2 μg/kg(μg/L)。方法操作简便,结果稳定可靠,可用于茚虫威对映体在番茄、葡萄和水样品中残留的分析。

Determination of indoxacarb enantiomers in tomato,grape and water by liquid chromatography-tandem mass spectrometry

A reversed-phase chiral method for the determination of indoxacarb enantiomers was established using liquid chromatography-tandem mass spectrometry(LC-MS/MS).The target analytes were quantified by external standard method,and the difference in matrix effect between matrix dispersed extraction and solid phase extraction was compared.The tomato and grape samples were extracted by acetonitrile and then purified by NH2/Carb solid phase extraction(SPE),while water was pre-concentrated and cleaned up by C18-H SPE cartridges.The chromatographic conditions were as follows:Chiralpak AD-RH column,V(acetonitrile)∶V(water)=65∶35,column temperature was 25 ℃,and flow rate was 0.4 mL/min.The results showed satisfied recoveries of the enantiomers in the range of 65.5%-117.0% at levels from 0.005 mg/kg(or mg/L) to 0.5 mg/kg(or mg/L) with relative standard deviations of 4.1%-18.1%(n=5).Limits of detection(LOD) of the enantiomers were in the range of 1.4-4.3 μg/kg(or μg/L),and limits of quantification(LOQ) were 4.7-14.2 μg/kg(or μg/L).The method is simple and suitable for the routine analysis of indoxacarb enantiomers in tomato,grape and water.