A competitive enzyme-linked immunosorbent assay (ELISA) was developed
for the quantitative
detection of fenpropathrin
[(RS)-α-cyano-3-phenoxybenzyl-2,2,3,3-tetramethylcyclopropanecarboxylate]. Polyclonal antisera were isolated from rabbits immunized
with two different fenpropathrin
hapten conjugates. One hapten contained an amino function; the
other contained a carboxyl group
for conjugation to carrier proteins. Mollusk hemocyanins,
thyroglobulin, and fetuin were used as
carrier proteins. The antisera varied greatly in their affinities
for fenpropathrin. A homologous
assay system using the coating antigen format was the most sensitive.
The IC50 for fenpropathrin
was 20 μg/L, and the lower detection limit was 2.5 μg/L.
Pyrethroids, such as phenothrin, permethrin,
resmethrin, fenvalerate, deltamethrin, cyfluthrin, and cypermethrin,
and the pyrethroid metabolites,
3-phenoxybenzoic acid and fenpropathrin acid, did not cross-react
significantly in this assay. Ten
percent acetone or methanol and a pH of 4 were determined to be optimum
assay conditions. Various
cationic, anionic, and nonionic detergents had no significant effect on
the assay.
Keywords: Fenpropathrin; pyrethroid; ELISA; pesticide; enzyme immunoassay;
cross-reactivity