Voltammetric Determination of L‐Dopa on Poly(3,4‐ethylenedioxythiophene)‐Single‐Walled Carbon Nanotube Composite Modified Microelectrodes

Abstract

In the present communication, it is shown that platinum microelectrodes electrochemically coated with a composite of poly(3,4-)ethylenedioxythiophene and single-walled carbon nanotubes (PEDOT/SWNT) enable determinations of 3,4-dihydroxy-l-phenylalaines (l-dopa) in neutral phosphate buffer solutions containing an excess of ascorbic acid. The interpenetrated networked nanostructure of the composite was characterized by scanning electron microscope (SEM) and Raman spectroscopy. It is shown that the presence of the composite gives rise to an increase in the electroactive area of an order of magnitude in compared to the area for the bare microelectrodes. The composite filmcoated microelectrode, which yielded reversible cyclic voltammograms for the ferro/ferricyanide redox couple for scan rates between 0.01 and 0.10 V s À1, also gave rise to two well-resolved oxidation peaks for l-dopa and ascorbic acid (AA). The latter effect, which was not seen in the absence of the composite, enabled differential pulse voltammetric determinations of l-dopa in the concentration range between 0.1 to 20 mM with a detection limit of 100 nM.

Selective determination of L-dopa in the presence of uric acid and ascorbic acid at a gold nanoparticle self-assembled carbon nanotube-modified pyrolytic graphite electrode

“…Xiang et al reported a multi-wall carbon nanotubes-Nafion modified glassy carbon electrode for the adsorption stripping voltammetry of Ldopa, with a detection limit of about 50 nM [28]. Mathiyarasu and Nyholm constructed a poly-(3,4-ethylenedioxythiophene)-singlewalled carbon nanotube composite-modified microelectrode and applied it to the electrochemical determination of L-dopa, with a detection limit of 0.1 M [29]. Shahrokhian and Asadian reported a glassy carbon electrode modified by a bilayer of multi-walled carbon nanotube and poly-pyrrole doped with tiron for the electrochemical determination of L-dopa in the presence of AA, with a detection limit of 0.1 M [30].…”

Electrochemical determination of levodopa in the presence of ascorbic acid by polyglycine/ZnO nanoparticles/multi-walled carbon nanotubes-modified carbon paste electrode

“…Also, it prepared a multi-walled carbon nanotubes-Nafion-modified glassy carbon electrode for the adsorption stripping voltammetry of L-dopa [32]. Mathiyarasu and Nyholm constructed a poly-(3,4-ethylenedioxythiophene)-single-walled carbon nanotube composite-modified microelectrode and applied it to the electrochemical determination of L-dopa [33]. At another research, a glassy carbon electrode modified by a bilayer of multi-walled carbon nanotube and poly-pyrrole doped with tiron used for the electrochemical determination of Ldopa in the presence of AA [34].…”

Electrochemical determination of L-dopa at cobalt hexacyanoferrate/large-mesopore carbon composite modified electrode

“…Chemically modified electrodes play an important role in reducing the high overvoltage required for the analyte determination. Some literatures have been reported for the electrochemical determination of L-dopa on chemically modified electrodes [15][16][17][18][19][20][21].…”