Fumonisin B Determination in Maize Products from Belize Using an Immunosensor Based on Screen-Printed Carbon Electrodes

A competitive electrochemical immunosensor, using screen-printed carbon electrodes (SPCEs), was developed for the determination of total fumonisins (sum of FB1, FB2 and FB3) extracted with a simple solvent extraction and dilution method, without clean up, from maize flour and maize tortillas. The optimized biosensor has a linear range of 0.25 to 50 µg/L with 3% and 2% reproducibility for FB1 and (FB1 + FB2), respectively, and a linear range of 0.25 to 10 µg/L with 2% reproducibility for (FB1 + FB2 + FB3). The limits of detection and quantification in PBS buffer for total fumonisins are 0.12 µg/L and 0.39 µg/L, respectively. These values in the maize matrix are 6.07 µg/kg and 20.25 µg/kg, respectively. In addition, the stability and the selectivity of the sensor were studied. The immunosensor was validated with liquid chromatography–tandem mass spectrometry. This novel biosensor is more rapid, simpler and cheaper than current methods, and can also be used at the point of need.