Simultaneous Determination of Ethylenebisdithiocarbamate (EBDC) and Propylenebisdithiocarbamate (PBDC) Fungicides in Vegetables, Fruits, and Mushrooms by Ultra-High-Performance Liquid Chromatography Tandem Mass Spectrometry

The present investigation concerns the development and validation of a simplified and sensitive method for simultaneous determination of ethylenebisdithiocarbamate (EBDC) and propylenebisdithiocarbamate (PBDC) fungicides in fruits, vegetables, and mushrooms. In this method, EBDCs and PBDCs were decomposed in an alkaline medium and derivatized with dimethyl sulfate to dimethyl ethylenebisdithiocarbamate (EBDC-dimethyl) and dimethyl propylenebisdithiocarbamate (PBDC-dimethyl), respectively. After the dispersive solid-phase extraction, the resulting methyl derivatives were analyzed by ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) operated in positive electrospray ionization mode within 5 min. In order to minimize the adverse impacts of the target compound degradation on data analysis, the stability of EBDC-dimethyl and PBDC-dimethyl both in solvent and matrix during the storage was evaluated. And the results indicated that EBDC-dimethyl and PBDC-dimethyl were sufficiently stable both in the extraction solvent (acetonitrile) and vegetal food sample matrices. The mean recoveries all through the procedure from EBDCs to EBDC-dimethyl and from PBDCs to PBDC-dimethyl in all matrices were in the range of 85.2-101.6% and 86.1-106.9%, respectively. The limits of quantification of the above two dithiocarbamate (DTC) fungicides were 0.4-1.0 mu g/kg in the form of EBDC-dimethyl, and 0.5-1.5 mu g/kg in the form of PBDC-dimethyl, respectively. As for mancozeb and propineb, the limits of quantification of these two representative DTCs fungicides in seven food matrices were within the range of 0.6-1.6 mu g/kg and 0.8-2.5 mu g/kg, respectively. The established method was applied for simultaneous determination of EBDC and PBDC fungicides in the real samples, indicating its performance in the surveillance of fungicidal dithiocarbamate residues in fruits, vegetables, and mushrooms samples.