DETERMINATION OF BROMOXYNIL AND IOXYNIL RESIDUES IN CEREALS AND SOIL BY GC-ITD

Bromoxynil and ioxynil have been determined in plants and soil by gas chromatography. These herbicides are extracted from soil samples with methylene chloride at acidic pH. Plant samples are extracted with a ba sic aqueous solution and extracts purified by solvent partitioning. He rbicide residues are submitted to perfluoroacylation prior to GC separ ation. These compounds are determined by ion-trap detection with singl e ion monitoring; N-(3-chloro-4 methyl-phenyl) perfluoropropyl amide i s used as internal standard. The detection limit of the method is near 0.001 mu g g(-1) for the samples studied. The proposed methods are se nsitive and reproducible enough to allow determination of these herbic ides at residue levels in plants and soil.