Poly-(3-methylthiophene)/carbon nanotubes hybrid composite-modified electrodes

The preparation of poly-(3-methylthiophene)—multi-walled carbon nanotubes hybrid composite electrodes is reported. The hybrid electrode shows a synergic effect of the electrocatalytic properties, and high active surface area of both the conducting polymer and carbon nanotubes, which gives rise to a remarkable improvement of oxidation of NADH with respect to polymer-modified electrodes, and CNTs-modified electrodes. SEM showed that carbon nanotubes served as nanosized backbone for P3MT electropolymerization. The amperometric NADH detection at +300 mV provided fast responses, a range of linearity between 5.0 × 10−7 and 2.0 × 10−5 mol l−1, and a detection limit of 1.7 × 10−7 mol l−1, which compares advantageously with those reported for other NADH CNT-based amperometric sensors. Furthermore, the direct electrochemistry of cytochrome c and FAD at the hybrid electrode is also checked.