Abstract:

A method for the determination of 55 fungicides in siraitia grosvenoriis by QuEChERS and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established. The samples were extracted with acetonitrile containing 1%(v/v) acetic acid, then dehydrated by anhydrous magnesium sulfate and purified by anhydrous sodium sulfate, N-propyl ethylenediamine (PSA) and C18. Then, 95% (v/v) acetonitrile aqueous solution (organic phase) and water (aqueous phase), both containing 0.005 mol/L ammonium formate and 0.01% (v/v) formic acid, were used as mobile phases with gradient elution. The compounds were tested by positive electrospray ion source (ESI⁺) and dynamic multiple reaction monitoring (DMRM) mode. Fifty-five fungicides were quantified by external standard method considering matrix effects. The correlation coefficients (R²) were greater than 0.99, which indicated that the linear dependence of the 55 fungicides were good in the range of 1.0-100.0 μg/kg. The LODs (S/N>3) and LOQs (S/N>10) of all the fungicides were 1.0 μg/kg and 10.0 μg/kg, respectively. The recoveries were in the range of 76.96%-118.45% and the relative standard deviations (RSDs) ranged from 3.44% to 19.63% (n=6). This method has the advantages of rapidity, accuracy and sensitivity for the high-throughput detection of fungicides residues in siraitia grosvenoriis.

Key words: dynamic multi-reaction monitoring (DMRM), fungicides, high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), QuEChERS, siraitia grosvenoriis