Analysis of photochemically induced cotton bound residues of deltamethrin by an immunoassay technique.

A sensitive and selective indirect competitive ELISA was developed for the detection of deltamethrin bound residues on cotton texture. Cross-reactivity studies with the main deltamethrin photodegradation products showed high specificity of deltamethrin polyclonal antibody to the parent compound. No cross-reactivity was measured with deltamethrin photodegradtion products derived from the alcohol moiety (3-phenoxybenzaldhyde, phenoxybenzyl alcohol, cyanohydrin, and 3-phenoxybenzoic acid), and lesser amounts were observed with the acid moiety (deltamethric acid). The dot-blot immunoassay was performed on cotton fabric discs spiked with deltamethrin and irradiated to assess the suitability of this system to detect bound residue. The dot-blot immunoassay results revealed that the bound form of deltamethrin has binding affinity with deltamethrin antibody similar to the parent compound. In addition, the test system was used to detect bound and free residues of deltamethrin on cotton samples exposed to three cycles of simulated sunlight and water wash. The results obtained suggest that the competitive ELISA format can be used as a tool for monitoring free and bound residues of deltamethrin impregnated on cotton targets.