Electrochemical detection of amino acids at carbon nanotube and nickel–carbon nanotube modified electrodes

Abstract

The oxidation and enhanced detection of traditionally 'non-electroactive' amino acids at a single-wall carbon nanotube (SWNT) surface and at a nickel hydroxide film electrochemically deposited and generated upon the SWNT layer is reported. Different CNT are compared, with Nafion-dispersed SWNT offering the most favorable layer for constant-potential amperometric detection. Factors affecting the oxidation process, including the pH or applied potential, are assessed. The response of the SWNT-Nafion coated electrode compares favorably with that of copper and nickel disk electrodes under flow injection analysis (FIA) conditions. The electrodeposition of nickel onto the SWNT-Nafion layer (Ni-CNT) led to a dramatic enhancement of the analytical response (vs. that observed at the SWNT or nickel electrodes alone). The oxidative process at the Ni(OH)(2) layer has been studied and the increase in sensitivity rationalized. In the presence of amino acid the Ni-CNT layer undergoes an electrocatalytic process in which the amino acid reduces the newly formed NiO(OH) species. Furthermore, the attractive response of both the CNT and Ni-CNT layers has allowed these electrodes to be used for constant-potential FIA of various amino acids and indicates great promise for monitoring chromatographic effluents. Once again an improved signal was observed at the Ni-CNT electrode compared to nickel deposited upon a bare glassy carbon electrode (Ni-GC).

Electrocatalytic properties of prussian blue nanoparticles supported on poly(m-aminobenzenesulphonic acid)-functionalised single-walled carbon nanotubes towards the detection of dopamine

“…They are essential and promising materials in the field of nano-science and nanotechnology because of their electronic properties and large surface area [1][2][3]. Their contribution to the improvement of electrical properties of some bare electrode such as the glassy carbon [4][5][6], graphite [7][8][9][10], carbon fiber [11], gold [12][13][14][15], and platinum (Pt) electrodes [16] have been reported. As part of its numerous applications, Han et al [17] considered CNTs as suitable mediators for prussian blue (PB)-modified electrodes because of their good electrical conductivity and the property of being particle carriers.…”

Electrodeposition of Nickel Hydroxide Nanoparticles on Carbon Nanotube Electrodes: Correlation of Particle Crystallography with Electrocatalytic Properties

“…Although, SWNTs are attracting considerable attention as a support for electrocatalytic materials, 22,[49][50] in the vast majority of cases, SWNT/NP composites are assessed by immobilizing, or producing, these structures on an electrode (typically glassy carbon) 49, 51-52 which has its own intrinsic electroactivity. In contrast, our approach examines the behavior of the SWNT/NP materials alone and thus circumvents any problems and contributions that may arise from the need to use a further electrode support.…”

“…[47][48][49] In this paper we compare the two different procedures for Ni(OH) 2 NP deposition on SWNT electrodes in terms of both the resulting crystalline phase of the Ni(OH) 2 and electrocatalytic performance towards the EtOH oxidation reaction (EOR) and…”

l -Cysteine determination in embryo cell culture media using Co (II)-phthalocyanine modified disposable screen-printed electrodes

“…Within the field of electroanalysis, previous studies describe that bare carbonaceous materials and conventional metallic electrodes (Au, Pt) usually exhibit high overpotentials for the electrooxidation of L-CySH due mainly to a sluggish electron transfer kinetic and, consequently, they exhibit short linear range concentration and low selectivity for LCySH determination [25][26][27]. To overcome these problems, various chemically modified electrodes (CMEs) and biosensors with electrocatalytic properties have been developed and applied for a superior determination of L-CySH [1][2][3][4][5][6][28][29][30][31][32][33][34]. In this sense, different types of materials have been employed to modify electrodes surface, e.g.…”