A Multiresidue Method for Determining 136 Pesticides and Metabolites in Fruits and Vegetables: Application of Macroporous Diatomaceous Earth Column

A fast and easy multiresidue method using the macroporous diatomaceous earth.(MDE) column for determining 136 pesticide and metabolite residues in fruits and vegetables was developed. The MDE column was used instead of the separation funnel for liquid/liquid partition in sample preparation. Through MDE columns, the preparation of test solution became easier and faster than traditional funnel liquid/liquid partition. The emulsion problem can also be avoided. Fifty one pesticides including acephate were determined by gas chromatography (GC) with a pulsed flame photometric detector (GC/PFPD) and 63 pesticides including aldrin were detected by GC with electron capture detection (GC/ECD). Twenty carbamate peticides and metabolites including aldicarb were determined by high performance liquid chromatography with a post-column derivaization system and a fluorescence detector (HPLC/FLD) and two benzimidazole pesticides including carbendazim and thiabendazole were detected by HPLC with an ultraviolet detector (HPLC/UV). Recovery studies were performed by spiking pesticides (0.05-2.0 ppm) in fruit and vegetable samples, and the triplicate results showed satisfactory recoveries and repeatability. The detection limits ranged from 0.003 to 0.2 ppm. The developed multireside method can be employed to other pesticides or matrices with an easier and less solvent consumption way to prepare sample solution. It is an environment-friendly and useful method for routine pesticide analysis.