Miniaturized Method Based on Matrix Solid-Phase Dispersion for the Rapid Screening of 36 Pesticides in Agricultural Food Commodities

Matrix solid-phase dispersion and gas chromatography-mass spectrometry were used for the rapid screening of 36 pesticides in agricultural products. Homogenized sample (0.5 g), C₈-modified silica (0.5 g) and Na₂SO₄ (1 g) were mixed and transferred to a cartridge containing activated silica (0.5 g). Best recoveries (>60%) were found using dichloromethane-ethyl acetate (4:1) for elution. Analytical characteristics at spiking levels (10–100 μg/kg) were calculated for each pesticide. Matrix effects were studied by comparing the slopes of the matrix-matched calibration curves. Fruit and vegetable samples from South Africa complied with EU and South African current regulation, except for cypermethrin in green beans.