Matrix solid-phase dispersion based on cucurbit[7]uril-assisted dispersive liquid-liquid microextraction coupled with high performance liquid chromatography for the determination of benzimidazole fungicides from vegetables.

A new method involving matrix solid-phase dispersion (MSPD) and dispersive liquid-liquid microextraction (DLLME) was optimized with the aid of stoichiometry and applied to the extraction, purification, and determination of benzimidazole residues in vegetables. Carbendazim, thiabendazole, and thiophanate-methyl were selectively extracted from vegetables using cucurbit[7]uril as the MSPD extractant and transferred to an aqueous solution, then further enriched using DLLME with acetonitrile and chloroform as dispersive and extraction solvents, respectively. The optimal extraction conditions of MSPD and DLLME were selected by two-level full-factorial design and central-composite design (CCD). The developed method (MSPD-DLLME-HPLC-UV) showed good linearity in the range of 0.025-5 μg/g, with R2 > 0.9984. Intra- and interday precisions were 5.3-10.9% and 10.6-12.4%, respectively, and the limit of detection was between 0.004 and 0.007 μg/g of fresh weight. This method was applied to the analysis of four different types of vegetables, and the recoveries ranged from 65.4% to 124.0%. The method was environmentally friendly, easy to operate, and sensitive.