Fabrication, characterization and application of carbon molecular wire electrodes for the determination of dopamine, uric acid and paracetamol

Abstract

Two molecular wires, trans-stilbene (STB) and trans,trans-1,4-diphenyl-1,3-butadiene (DPBD), as binders and two carbonaceous materials, multi-walled carbon nanotubes (MWCNTs) and graphite, as conductive phases were used to fabricate carbon composite electrodes so called carbon molecular wire electrodes (CMWEs). Cyclic voltammetry studies using [Fe(CN)₆]^3-/4- as general redox probes revealed that the prepared CMWEs using MWCNTs present superior electrochemical properties compare to that prepared using graphite. So, MWCNTs were selected as the conductive phase and two CMWEs were fabricated using STB and DPBD as binders. Thereafter, the electroanalytical properties of the fabricated CMWEs were evaluated for the determination of dopamine, uric acid and paracetamol using differential pulse voltammetry (DPV). Linear relationships were observed between the peak current intensity of DPV responses and concentrations of DA, UA and PA in the range between 1.0 × 10⁻⁶ and 1.0 × 10⁻⁴ M for both CMWEs prepared by STB and DPBD. The limits of detection for the determination of DA, UA and PA were 0.1, 0.4 and 0.2 μM using CMWE prepared by STB and 0.2, 0.3 and 0.3 μM using CMWE prepared by DPBD, respectively. The relative standard deviations of DPV responses towards the investigated analytes using both CMWEs for reproducibility (n = 5) and repeatability (n = 5) studies were better than 4.0 %. The effect of the presence of possible interfering species on analyte signals was examined and the fabricated CMWEs were then applied for the determination of DA, UA and PA in human blood serum samples.