Determination of phosphorus-containing pesticides by the catalytic method on thin-layer chromatography plates

The oxidation reaction of o-dianisidine with hydrogen peroxide, which is catalyzed by phosphorus-containing pesticides, was conducted at the surface of silica. Although the reaction products at the surface of an adsorbent and in solution are the same, the reaction rate on the adsorbent is higher. Because of this, the absolute detection limits of Metaphos and Fozolone can be decreased by 1-2 orders of magnitude in comparison with their determination in solution. It was demonstrated that the reaction proposed can be used for the detection of these pesticides by thin-layer chromatography with c(min) 0.6-0.7 mu g. The accuracy of the procedure was tested in the analysis of apples.