POLARIZATION FLUOROIMMUNOASSAY OF THE HERBICIDE DICHLORPROP

A polarization fluorescence immunoassay has been developed for the scr eening of the herbicide dichlorprop [(+/-)-2-(2,4-dichlorophenoxy)prop anoic acid]. The assay is based on the difference in fluorescence pola rization between free and antibody-bound fluoresceinamine-labeled dich lorprop. Antibodies toward dichlorprop were produced by immunizing a r abbit with conjugates of dichlorprop to bovine serum albumin. Polariza tion measurements were performed by using two spectrofluorometers whic h use different optic configurations. Calibration curves fitted to an IC50 four-parameter logistic model gives chi-square 10(-5). The upper end of the standard curve for polarization fluorescence immunoassay is 0.01 mug/mL and the lower end 100 mug/mL. The method offers good anal ytical specifications and little cross-reactivity against similar comp ounds. The proposed method is compared with enzyme-linked immunosorben t assay using the same set of reagents. The effectiveness of the metho d on real samples was checked in spiked apple samples.