干旱区生态环境知识资源中心

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 C-18 (150 mmx2.1 mm i.d., 3.5 mu m) column. Studies at fortification level of 0.05-25 mu g/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 mu g/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 mu g/kg in tomato sample.