Sand as a solid support in ultrasound-assisted MSPD: A simple, green and low-cost method for multiresidue pesticide determination in fruits and vegetables.

Sand was studied as a solid support in ultrasound-assisted matrix solid-phase dispersion (UA-MSPD) for the extraction of different pesticide classes, including organophosphates, carbamates, triazoles and pyrethroids from fruits and vegetables, with determination by GC-MS and LC-MS/MS. The performance of sand was compared with that of different types of classic solid supports and alternative natural materials from renewable sources. The best results were obtained using 0.5 g sample, 1 g sand as a solid support, 20 mg activated charcoal and 5 mL ethyl acetate as elution solvent. Recoveries ranged from 55 to 140% with an RSD ≤ 20%. LOQs varied from 0.005 to 0.5 mg kg-1 for all analytes. Thiamethoxam, captan, chlorpyrifos, dimethoate and pyrimethanil were found in strawberry samples at concentrations from 0.01 to 0.06 mg kg-1. Acephate and tebuconazole were found in a tomato sample at concentrations of 0.45 and 0.30 mg kg-1, respectively. The method developed was efficient, simple, cheap, robust, and environmentally friendly.