Determination of Methyl 2-Benzimidazolecarbamate in Blueberries by Competitive Inhibition Enzyme Immunoassay

Abstract

Abstract A polyclonal enzyme Immunoassay (EIA) method was developed that will quantitate methyl 2- benzlmidazolecarbamate (MBC), the degradation product of benomyl, In blueberries. The entire analysis Is completed within 25 min, and up to 8 samples can be analyzed simultaneously with a detection limit of 18 ppb. The assay response was linear from 0.69 to 22 ppb MBC. Cross-reactivity was confined to the benzimidazole and dicarboxlm- Ide type pesticides. Intra-assay percent coefficients of variation (% CVs) ranged from 3.4 to 18.4 for the standards, and from 3.2 to 20.6 for the samples. Interassay % CVs varied from 7.5 to 22.3 for the standards, and from 7.5 to 22.0 for the samples. Correlation coefficient between immunoassay and liquid chromatography was 0.87 for the methanol extract and 0.98 for the methylene chloride partition of the methanol extract containing 100 mL 1% sodium chloride. None of the 40 field samples analyzed approached the tolerance of 15 ppm (mean of 20 positive samples was 55 ppb). The ability of the EIA to monitor MBC easily and Inexpensively at concentrations far below the tolerance has major implications for current dietary risk assessment methods.