HOMOGENEOUS ENZYME-IMMUNOASSAY FOR PYRETHROID PESTICIDES AND THEIR DERIVATIVES USING BACILLARY ALPHA-AMYLASE AS LABEL

A new enzyme immunoassay for detection of some pyrethroid pesticides ( permethrin, phenothrin) and their derivatives containing 3-phenoxybenz oic group has been developed. It is based on enzyme multiplied immunoa ssay technique (EMIT), modulation of catalytic activity of hapten-enzy me conjugate by anti-hapten antibodies and restoring the initial activ ity level by free hapten in the sample tested. Alpha-amylase from Baci llus subtilis is proposed as a new enzyme label for EMIT. Inhibition o f the 3-phenoxybenzoic acid-amylase conjugate by specific antibodies w as revealed at the systems detecting non-splinted starch or released a ldehyde groups. EMIT conditions for pyrethroid pesticides and their de rivatives have been optimized. The assay time is not more than 45 min, the detection limits reach 2-5 ng ml(-1). Photometric measurements ca n be carried out by means of standard ELISA equipment. The proposed la bel was also used to develop EMIT for pesticide 2,4-dichlorophenoxyace tic acid.