DETERMINATION OF METHYL 2-BENZIMIDAZOLECARBAMATE IN BULK FRUIT JUICE CONCENTRATES BY COMPETITIVE-INHIBITION ENZYME-IMMUNOASSAY

A polyclonal enzyme immunoassay (EIA) was used to quantitate methyl 2- benzimidazolecarbamate (MBC or carbendazim), a degradation product of benomyl, in bulk fruit juice concentrates. These concentrates are used by industrial producers to prepare juice or juice concentrates sold i n supermarkets. Total sample analysis time was less than 18 min withou t cleanup or 35 min with cleanup. As many as 8 samples can be analyzed simultaneously, with a limit of quantitation of 10 ppb. The assay's d ynamic range ran from 0.5 to 20 ppb MBC but was best from 0.5 to 10 pp b. Intra-assay coefficients of variation (CVs) varied from 4.0 to 13% for standards and from 4.1 to 26% for samples. Interassay CVs varied f rom 4.5 to 47% for standards and 5.6 to 22% for samples. Average recov ery of several juice concentrates spiked at 10 to 290 ppb was 97%. A t otal of 140 juice concentrates comprising 20 different kinds of juice were analyzed by 2 EIA methods and one liquid chromatographic (LC) pro cedure. MBC-positive samples gave the following correlation coefficien ts: 0.954 for EIA without cleanup vs LC, 0.956 for EIA with cleanup vs LC, and 0.978 for EIA with cleanup vs EIA without cleanup. MBC concen trations in MBC-positive juice samples ranged from 5 to 2960 ppb.