Copper nanoparticles/poly-3-methylthiophene composite: Synthesis, characterization and catalytic application to enzyme-less glucose detecting

The present work describes the preparation and the characterization of a composite nanomaterial obtained by the electrochemical deposition of copper nanoparticles (CuNPs) on an electrosynthesized film of poly-3-methylthiophene (P3MT). Copper electrodeposition was achieved by applying a potential pulse program both on Pt and on screen-printed electrodes (SPEs). The microscopic characterization of the composite film by scanning electron microscopy (SEM) suggested that the applied pulse width is correlated to the amount of the deposited particles but it does not influence CuNPs size. The nanocomposite was analyzed also by X-ray Photoelectron Spectroscopy (XPS) confirming the influence of the pulse width on the amount of electrodeposited copper and evidencing the presence of Cu(I) and Cu(II) species in each sample. For a comparison, CuNPs were prepared from solutions of both CuCl2 and Cu(ClO4)2. XPS analysis evidenced the stabilizing effect of Cl− ions on CuNPs promoting their entrapment in P3MT film also when the composite film is exposed to carrier solution in a flow system, contrarily to what observed in the presence of ClO4− ions. Performed electrochemical tests showed that CuNPs/P3MT exhibited a remarkable electrocatalytic activity for glucose oxidation. The composite film deposited on SPEs was successfully used for glucose electrochemical detection in a flow system. The effect of the applied potential and of the flow rate of carrier stream was evaluated: under the selected optimal condition the composite film exhibited a satisfactory response in terms of detection limit, linear range and repeatability. The sensitivity of CuNPs/P3MT to other compounds (ascorbic acid, uric acid, sorbitol, fructose, dopamine) was verified evidencing that the proposed system could be effectively used as an electrochemical detector coupled to a chromatographic system for the simultaneous detection of biomolecules