Analysis of fumonisin B1 in corn by capillary electrophoresis

Intact fumonisins contain two tricarballylic acid groups and can therefore acquire a net negative charge. The anionic nature of the fumonisins is the basis behind the widely used method for cleanup of corn with strong anion exchange (SAX) columns. This property also enables the fumonisins to be separated by electrophoretic techniques which, until now, have not been applied to the analysis of fumonisins in corn. Fumonisin B1, extracted from corn with 80/20 (v/v) methanol/water and isolated with a commercially available affinity column, was derivatized with fluorescein isothiocyanate for analysis by capillary zone electrophoresis with laser-induced fluorescence detection (CZE-LIF). Recoveries from corn fortified with 0.25 to 5.0 ppm FB1 averaged 89% (range 71 to 102%). As little as 0.05 ppm FB1 could be detected in corn. For corn naturally contaminated with FB1, the CZE-LIF method compared favorably to established SAX/HPLC and C18/HPLC methods. Capillary electrophoresis can be used for quantitation of FB1 in corn, with minimal use of organic solvents and provides an additional tool for confirming fumonisin contamination.