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 ca talyzed by phosphorus-containing pesticides, was conducted at the surface o f 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. Be cause of this, the absolute detection limits of Metaphos and Fozolone can b e decreased by 1-2 orders of magnitude in comparison with their determinati on in solution. It was demonstrated that the reaction proposed can be used for the detection of these pesticides by thin-layer chromatography with c(m in) 0.6-0.7 mu g. The accuracy of the procedure was tested in the analysis of apples.