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), C-8-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 mu g/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.