A Highly Sensitive Electrochemical Immunosensor for Fumonisin B 1 Detection in Corn Using Single‐Walled Carbon Nanotubes/Chitosan

A sensitive electrochemical immunosensor was developed for detecting fumonisin B 1 (FB 1 ) in corn using the single‐walled carbon nanotubes/chitosan. The detection mechanism of immunosensor was based on an indirect competitive binding to a fixed amount of anti‐FB 1 between free FB 1 and FB 1 ‐bovine serum albumin, which was conjugated on covalently functionalized nanotubes/chitosan laid on the glass carbon electrode. The anti‐rabbit immunoglobulin G secondary antibody labeled with alkaline phosphatase was then bound to the electrode surface through reactisubstrate α‐naphthyl phosphate, which produced electrochemical signal. Under optimized conditions, this method could detect FB 1 from 0.01 to 1000 ng mL −1 with a detection limit of 2 pg mL −1 . This is well below the detection limit required from European Union legislation, 2–4 mg L −1 . Moreover, good recoveries were obtained for the detection of spiked corn samples and actual corn samples. As the method has good sensitivity and recovery for detecting FB 1 , it is a practical detection method.