SOLID-PHASE EXTRACTION COMBINED WITH DISPERSIVE LIQUID-LIQUID MICROEXTRACTION FOR THE DETERMINATION OF THREE BENZIMIDAZOLE PESTICIDES (CARBENDAZIM, THIABENDAZOLE, AND THIOPHANATE-METHYL) IN TOMATOES

摘要

A simple, inexpensive, and reliable analytical method was developed to determine the benzimidazole residues in tomato using high performance liquid chromatography (HPLC). Sample pretreatment using solid-phase extraction (SPE) to remove the matrix and dispersive liquid-liquid microextraction (DLLME) to enrich the analytes was performed. For SPE, different sorbents and different elution processes were tested. For DLLME, the parameters affecting the extraction efficiency, such as the type and volume of extraction solvent, type and volume of the elution solvent (disperser solvent), pH, and salt addition, were examined and optimized. The method combining the advantages of SPE and DLLME showed higher selectivity and sensitivity than the conventional extraction method, and was applied successfully to determine trace levels of the benzimidazoles pesticide in tomatoes.