A quantitative enzyme-linked immunoassay for the detection of 2,6-dichlorobenzamide (BAM), a degradation product of the herbicide dichlobenil

2,6-Dichlorobenzamide (BAM) is the dominant degradation product in soil of the widely used herbicide dichlobenil. To detect BAM in water, a highly sen sitive and specific enzyme-linked immunosorbent assay (ELISA) was developed . As an alternative to conventional coating of ELISA plates, the assay is b ased on direct covalent immobilisation. We achieved a surface which require s a short time for the immobilisation of ligand, is stable under dry storag e, and which permits assays with a low CV. The performance of the assay was demonstrated by an inter-well CV that was generally less than 6%, a detect ion limit (DL15) of 0.02 mu g/l and an IC50 of 0.19 mu g/l. Cross-reactivit y was measured against nine analytes with structural homology to BAM. The h ighest degree of cross-reactivity (10.8%) was seen with 2,6-dichlorothioben zamide (Chlorthiamid). Considering an EU-limit of 0.1 mu g/l as the permiss ible maximum for the presence of pesticides in drinking water, this ELISA-p rocedure is suitable for large-scale screening of water samples suspected o f being contaminated with BAM. (C) 2000 Elsevier Science B.V. All rights re served.