Label Free Poly(2,5-dimethoxyaniline)–Multi-Walled Carbon Nanotubes Impedimetric Immunosensor for Fumonisin B(1) Detection

An impedimetric immunosensor for fumonisin B(1) (FB(1)) was developed from a poly(2,5-dimethoxyaniline)-multi-walled carbon nanotube (PDMA-MWCNT) composite on the surface of glassy carbon electrode (GCE). The composite was prepared electrochemically and characterized using cyclic voltammetry. The preparation of the FB(1) immunosensor involved the drop-coating of a bovine serum albumin mixture of the anti-fumonisin antibody (anti-Fms) onto the composite polymer-modified GCE. The electrochemical impedance spectroscopy (EIS) responses of the FB(1) immunosensor (GCE/PDMA-MWCNT/anti-Fms) have a linear range of 7 to 49 ng·L(−1), and the corresponding sensitivity and detection limits are 0.272 kΩ L·ng(−1) and 3.8 pg·L(−1), respectively. The limit of detection of the immunosensor for certified corn sample (i.e., certified reference material) is 0.014 ppm FB(1), which is in excellent agreement with the value published by the vendors and significantly more accurate than that obtained with enzyme-linked immunosorbent assay (ELISA).