Determination of 9 Strobilurin Fungicides in Vegetables by QuECHERS-Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry

The method was established for the nine strobilurin fungicides in vegetables by using QuEChERS method. The samples were extracted with acetonitrile and purified with n-propyl-ethylenediamine (PSA), C₁₈ and graphitized carbon black (GCB) by orthogonal test. Using 0.05% formic acid water and 0.05%formic acid acetonitrile as mobile phase gradient elution, the target compounds were separated by Shimadzu shim pack C₁₈ column (2.1 mm×50 mm, 2 μm) and determined in positive ion mode. The linear relationship of 9 strobilurin fungicides was good in the range of 1～100 ng/mL, the coefficient of determination was between 0.9942～0.9995. The LOD was 0.05～0.3 μg/kg and the LOQ was 0.2～0.9 μg/kg. At the levels of 2, 10 and 20 μg /kg, the recovery rates of the five vegetables were 77.26%～111.73%, and the relative standard deviation was 0.46%～6.59%. The method is accurate, rapid, convenient and sensitive, which can meet the requirements of trace detection of nine strobilurin fungicides in vegetables.