Abstract
The method of the systematic identification and determination of pesticides was attempted by a combination of column, thin-layer and gas chromatography. Many kinds of pesticides were classified into six divisions and twenty two groups by thin-layer chromatography (tlc), and further divided into six fractions corresponding to divisions by column chromatography. In this paper, in order to apply this systematic method to the determination of pesticide residue in crops, food products or soils, an extract procedure, solvent partitioning and Florisil column cleanup procedures were decided with feed stuff-corns, which had some difficulty in analysis because of being rich in oils and coloring materials. Furthermore, recovery experiments at the level of residue analysis were performed to evaluate the efficiency of this systematic method. Fifteen pesticides in the First and Second Divisions containing tetrasul, heptachlor, quintozene, CNP, chlorpyrifos and nitrogen, etc. were mostly eluted into Fractions I and II from a silica column, respectively, and recovered approximately 100%. Twelve pesticides in the Second Division containing trifluralin, leptophos, dichlofenthion, dichlobenil and chlorfenson, etc. were mostly eluted into Fraction II and recovered more than 90%, except for chlorothalonil.
