A POLARIZATION FLUORESCENCE IMMUNOASSAY FOR THE HERBICIDE PROPANIL

Abstract

A rapid, homogeneous polarization fluorescence immunoassay (PFIA) has been developed for herbicide propanil. Polyclonal antiserum were raised in rabbits using 3,4-dichloroaniline coupled to succinylated bovine serum albumin (BSA) as immunogen. The various haptens and fluorescein-labeled tracers were synthesized to achieve high-sensitivity PFIA. The method can detect propanil concentrations in the range 1–100 ng/mL in 50 μL of sample. Analysis of one sample takes less then 1 min. In order to achieve better sensitivity a preconcentration step is possible and has been done for the low concentration samples. The use of SPE was suitable to enrich the sample, allowing measuring water samples at the limit required at EC Directive (permitted residue level in water: 0.1 ng/ml). The specificity of the PFIA for propanil was investigated using chloranilines, phenylureas, and other pesticides. Some cross-reactivity was found for closely related phenylureas (13–18%), but the major metabolite 3,4-dichloroaniline had negligible cross-reactivity (0.1%). SPE-PFIA and SPME-GC-MS showed a good correlation, when testing propanil in drinking water.

Keywords:

• Herbicides
• Propanil
• Polarization fluorescence immunoassay
• Specificity

ACKNOWLEDGMENTS

This work was supported by EC INCO-COPERNICUS Grants ERBIC-15CT-96-0802 and ERBIC-15CT-98-0910. Anna Krasnova is grateful to the Robert Havemann Foundation for a Scholarship.