| Abstract
| - A fluorescent excitation transfer immunoassay for spinosyn A, a fermentation derived insect controlagent, has been developed and applied to the analysis of tap water and wastewater effluent frommanufacturing plants. Fluorescein (F) and tetramethylrhodamine (TMR) were chosen as donor andquencher, respectively, for the excitation transfer. Fluorescence quenching was observed from thebinding of F-labeled antigen to TMR-labeled antibody. By employing nonlabeled antigen in acompetitive immunoassay format, we reversed fluorescence quenching. The assay provides a limitof detection of 0.01 ppb and a working range of 0.05−1 ppb and allows for the rapid determinationof spinosyn A in water with recovery values ranging from 96% to 120%. With the exploitation of thesmall size of optical fibers, fluorescence from an assay volume of 24 μL could be measured withoutspecial vessels. Keywords: Immunoassay; fluorescent excitation transfer; spinosyn; fiber optic; water
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