DEVELOPMENT OF IMMUNOASSAYS FOR TYPE-II SYNTHETIC PYRETHROIDS - 2 - ASSAY SPECIFICITY AND APPLICATION TO WATER, SOIL, AND GRAIN

Cross-reactions of a panel of immunoassays developed for type II (alph a-cyano-) synthetic pyrethroids were evaluated with type I and II comp ounds. Cross-reactions of both groups were affected by alkali treatmen t. The treatment typically increased sensitivities of type II compound s, and decreased cross-reactions of type I compounds. After isomerizat ion, each of the 12 combinations studied provided more sensitive detec tion of deltamethrin than the other compounds, even in the case of ant isera and enzyme conjugates based on cypermethrin, cyhalothrin, or the ir fragments. Several immunoassays were selective for deltamethrin. As says with the broadest specificities detected type I and II compounds with IC50 values of 20-400 mu g/L. None of the assays detected compoun ds lacking a cyclopropane ring (fenvalerate, fluvalinate). Spike and r ecovery studies for deltamethrin in water, soil, and wheat grain indic ated that the selected immunoassays quantified it with high precision and good recoveries. Good correlations between immunoassay and gas chr omatography/mass spectrometry data were also obtained for incurred res idues of deltamethrin and bifenthrin extracts of water and soil sample s.