QuEChERS-GC-MS/MS Detetermination of Residual Amount of 6 Methoxy Acrylate Fungicides in 3 Edible Mushrooms

An analytical method for determination of 6 methoxy acrylate fungicides (picoxystrobin, kresoxim-methyl, fluacrypyrim, dimoxystrobin, pyraclostrobin and fluoxastrobin) in the 3 edible mushrooms by QuEChERS-GC-MS/MS was established in the work. 25.0 g of the crushed edible mushrooms samples were taken, and mixed with by 25 mL of cyclohexane-ethyl acetate solution at a volume ratio of 1:1 to extract the 6 fungicides by shaking. The mixture was vortexed and freeze-centrifuged after adding the QuEChERS extraction package. The extracted solution was then transferred to PSA purification tube. After vortexing and centrifuging, 10 mL of the supernatant was taken and evaporated to near-dryness by N₂-blowing at 60℃. 1 mL of cyclohexane-ethyl acetate solution at a volume ratio of 1:1 was added to the residue, and the mixture was dissolved by swirling, and filtered through 0.22 μm filter membrane. The filtrate was introduced to Rtx-5 MS chromatographic column and separated under the condition of split-flow sample introduction and programmed temperature elevation with helium gas as carrier, and then analyzed by MS/MS with EI and MRM mode. External standard method was used in quantitative analysis. Linearity relationships between values of mass fraction of the 6 fungicides and its respective peak areas were found in the same range of 0.02-2.0 mg·L^-1, with detection limits (3S/N) of 0.001-0.003 mg·kg^-1. Test for the spiked recovery were made at 3 concentritions for the 3 edible mushrooms such as shiitake mushrooms, coprinus comatus and enoki mushrooms, giving results of recovery ranged from 83.5% to 105%. Values of RSDs (n=6) found were in the range of 1.7%-5.0%, with RSDs (n=6) of repeatibility less than 5.0%.