Development of competitive immunoassays to hydroxyl containing fungicide metabolites

Abstract

This paper describes the isolation of monoclonal antibodies and the development of competitive immunoassays to pesticide metabolites of the fungicides imazalil, carbendazim and thiabendazole. The metabolite specific hydroxyl residues were used as the reactive group with which to link the metabolite to the carrier proteins Keyhole Limpet Haemocyanin (KLH) and Bovine Serum Albumin (BSA). In each case immune responses in mice were raised and monoclonal antibodies were produced. Antibodies were developed into competitive ELISAs to the appropriate metabolite. The antibody raised to a metabolite of imazalil was optimised into a competitive ELISA format which had an assay IC50 of 7.5 μg/L and a limit of detection (LOD) of 1.1 μg/L. A single antibody isolated against the metabolite of carbendazim had assay IC50s of 3.2 and 2.7 μg/L for the metabolites of carbendazim and thiabendazole respectively with an LOD of 0.38 μg/L for both. These sensitive immunoassays may have application in the monitoring of human exposure to these fungicide residues either by occupational or non-occupational routes.

Keywords:

• Benzimidazole fungicide
• carbendazim
• thiabendazole
• imazalil
• urinary metabolite
• ELISA assay

Acknowledgments

The work described was funded by the UK Food Standards Agency. We are indebted to the late Professor Garry Whitelam who assisted in the planning of this work.