A comparative study of indirect competitive ELISA and HPLC for fumonisin detection in corn of the state of Parana, Brazil

The performance of a monoclonal antibody (MAb)-based indirect competitive E LISA (IC-ELISA) for fumonisin detection in corn was valuated using 150 post -harvest corn samples from the April 1995 and March-April 1996 crop, in the State of parana, Brazil. Compared to high performance liquid chromatograph y (HPLC), the correlation coefficient (r) of the results from the two metho ds was 0.94. The IC-ELISA detected total fumonisin levels of 1.1 to 1.5-fol d higher than HPLC in 85 samples (56.6%). The concentration range of 1.0 to 5.0 mu g g(-1) was observed in 26% of samples analysed by ELISA and in 29% by HPLC. In addition, four samples (2.7%) showed an ELISA/HPLC ratio of 0. 7 to 0.99 and seven samples (4.7%) a 1.0 ratio. In 29 (13.3%) samples, IC-E LISA detected 1.6 to 2.0-fold higher values than HPLC. These data showed hi gh correlation (r = 0.91) of IC-ELISA and HPLC for fumonisin concentration in corn contaminated with less than or equal to 10 mu g g(-1), with a detec tion limit of 93 ng g(-1). Matrix interference was minimized by diluting th e sample before the ELISA assay. MAb-based IC-ELISA may be effectively appl ied for fumonisin screening in corn, with advantages of simplicity, ease of sample preparation and sensitivity.