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 ELISA (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 chromatography (HPLC), the correlation coefficient (r) of the results from the two methods was 0.94. The IC-ELISA detected total fumonisin levels of 1.1 to 1.5-fold 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-ELISA detected 1.6 to 2.0-fold higher values than HPLC. These data showed high 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 detection limit of 93 ng g(-1). Matrix interference was minimized by diluting the sample before the ELISA assay. MAb-based IC-ELISA may be effectively applied for fumonisin screening in corn, with advantages of simplicity, ease of sample preparation and sensitivity.