Pesticide residues are determined by thin layer chromatography (TLC) using the Hill reaction as a detection method. Tomatoes samples without pesticide were fortified with atrazine, diuron, chloroxuron and metribuzin, and were applyed in silica gel plates with the help of a microsyringe. The pesticides were elued with ethyl acetate. There was no need of cleaning up because no interference was noticed. After the revelation of the plates, the diameters of the spots were measure by using a rule. The range of the determined concentration for all the pesticides was from 0.1 to1.0 ng/muL. The results obtained through TLC can be used for semi-quantitative analysis.The results obtained were compared to gas and liquid chromatography, showing good agreement between both techniques.
tomatoes; Hill reaction; thin layer chromatography
