高效液相色谱-串联质谱法测定蔬菜和水果中氟吗啉的残留量

建立了高效液相-串联质谱法(LC-MS/MS)分析蔬菜和水果中氟吗啉残留量检测的方法。通过氟吗啉光照实验,研究了氟吗啉顺反异构体转化规律。以醚菌胺为内标(I.S.),乙酸乙酯提取,经HLB(亲水-疏水净化住)固相萃取小柱净化并富集后,以液相色谱分离,采用质谱正离子多反应监测模式进行定量分析。方法定量限为0.05μg/kg;线性范围为0.05～25μg/kg;提取回收率为77.64%～92.83%;相对标准偏差均小于8.6%。本方法灵敏度高、选择性好,实际样品检测中的检出率达到70%;样品中最高残留量为1.83μg/kg,能满足蔬菜和水果中氟吗啉残留量检测要求。

Determination of Flumorph Residues in Vegetables and Fruits by High Performance Liquid Chromatography-Tandem Mass Spectrometry

A method was developed for the determination of flumorph residues in vegetables and fruits using dimoxystrobin as internal standard(IS) by high performance liquid chromatography-tandem mass spectrometry(LC-MS/MS).The conversion rule between flumorph(Z) and flumorph(E) has been studied by sunlight test of flumorph.Flumorph and IS were extracted with ethyl acetate,then purified and concentrated by Oasis HLB cartridge.Qualitative and quantitative detection for the analytes were carried out under the multiple reaction monitoring(MRM) in positive ion mode after the chromatographic separation on Symmetry C18(150 mm×2.1 mm i.d.,3.5 μm) column.Studies at fortification level of 0.05-25 μg/kg gave mean recoveries from 77.6%-92.8% for flumorph,with relative standard deviation(R.S.D.) ≤8.6%.The limit of quantification(LOQ,S/N=10) was 0.05 μg/kg.The proposed method was successfully applied to real samples from different kinds of vegetables and fruits.Flumorph residues were detected in 70% of the samples analyzed and the highest concentration level was 1.83 μg/kg in tomato sample.