Electrocatalytic reduction of NAD+ at glassy carbon electrode modified with single-walled carbon nanotubes and Ru(III) complexes |
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Authors: | Abdollah Salimi Mohadeseh Izadi Rahman Hallaj Saied Soltanian Hassan Hadadzadeh |
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Institution: | (1) Department of Chemistry, University of Kurdistan, P.O. Box 416, Sanandaj, Iran;(2) Research Center for Nanotechnology, University of Kurdistan, P.O. Box 416, Sanandaj, Iran;(3) Department of Chemistry, Isfahan University of Technology, Isfahan, Iran |
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Abstract: | A simple procedure was developed to prepare a glassy carbon electrode modified with carbon nanotubes and Ruthenium (III) complexes.
First, 25 μl of dimethyl sulfoxide–carbon nanotubes solutions (0.4 mg/ml) was cast on the surface of the glassy carbon electrode
and dried in air to form a carbon nanotube film at the electrode surface. Then, the glassy carbon/carbon nanotube-modified
electrode was immersed into a Ruthenium (III) complex solution (direct deposition) for a short period of time (10–20 s for
multiwalled carbon nanotubes and 20–40 s for single-walled carbon nanotubes). The cyclic voltammograms of the modified electrode
in aqueous solution shows a pair of well-defined, stable, and nearly reversible redox couple, Ru(III)/Ru(II), with surface-confined
characteristics. The attractive mechanical and electrical characteristics of carbon nanostructures and unique properties and
reactivity of Ru complexes are combined. The transfer coefficient (α), heterogeneous electron transfer rate constants (k
s), and surface concentrations (Γ) for the glassy carbon/single-walled carbon nanotubes/Ru(III) complex-, glassy carbon/multiwalled carbon nanotubes/Ru(III)
complex-, and glassy carbon/Ru(III) complex-modified electrodes were calculated using the cyclic voltammetry technique. The
modified electrodes showed excellent catalytic activity, fast response time, and high sensitivity toward the reduction of
nicotinamide adenine dinucleotide in phosphate buffer solutions at a pH range of 4–8. The catalytic cathodic current depends
on the nicotinamide adenine dinucleotide concentration. In the presence of alcohol dehydrogenase, the modified electrode exhibited
a response to addition of acetaldehyde. Therefore, the main product of nicotinamide adenine dinucleotide electroreduction
at the Ru(III) complex/carbon nanotube-modified electrode was the enzymatically active NADH. The purposed sensor can be used
for acetaldehyde determination. |
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Keywords: | CNTs Ru(III) complexes Glassy carbon NAD+ Alcohol dehydrogenase Acetaldehyde Sensor |
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