The organophosphorus pesticides are frequently applied in tomato cultivation in Brazil. In the present work an analytical methodology for quantification of the organophosphorus pesticides: acephate, chlorpyrifos, malathion, methamidophos and parathion-methyl residues in tomatoes was developed and validated using Gas Chromatography with a Nitrogen-Phosphorus Detector (GC-NPD). The possibility of a matrix effect was studied. Analytical curves prepared in an extract of the matrix were linear from 0.006 to 0.80 mg L-1. The precision studies supplied results with RSD <15%. The recoveries of the pesticides calculated from the curve prepared in the matrix extract were between 88 and 118%. With the proposed procedure quantification limits between 0.0132 and 0.135 mg kg-1 were obtained.
pesticide residues; organophosphorus; GC-NPD; tomato
