Preparation of voltammetric biosensor for tryptophan using multi-walled carbon nanotubes

Abstract

Multi-walled carbon nanotubes (MWCNTs) were grown by chemical vapor deposition. The effect of the composition of carbon paste electrode on its voltammograms was evaluated in basic solution with 5.0×10 −5 M tryptophan (Trp). It was found that addition of MWCNTs to the carbon paste would generate the peak current of Trp because of its catalytic effect on the redox process. The pH strongly affects the peak potential of Trp. The best analytical response was obtained at pH 13.0. The anodic peak currents were proportional to Trp concentrations in the range of 1.0×10 −9 -1.0×10 −4 M under the optimized experimental conditions. The detection limit was 2.2×10 −10 M. The effect of potential scan rate on the peak potential and peak current of tryptophan was investigated. The correlation of the peak currents against v 1/2 (v is the scan rate) is linear, which is very similar to a diffusion-controlled process. The proposed biosensor was applied to the determination of Trp in pharmaceuticals formulations successfully.

Novel microfluidic graphene oxide–protein amperometric biosensor for detecting sulfur compounds

“…A broad spectrum of methods, including iodic methods , polarography , spectrophotometry , chromatography , potentiometry , amperometry , voltammetry , and surface plasmon resonance , has been used for detection of sulfide species. Among these methods, biosensors have received extensive attention because of their significant advantages including high selectivity, fast response , and real‐time analysis .…”

Poly-dopamine-Beta-Cyclodextrin Modified Glassy Carbon Electrode as a Sensor for the Voltammetric Detection of L-Tryptophan at Physiological pH

“…as component of dietary protein while it is scarcely present in vegetables. Hence, it has been supplied through food products to avoid its de iciency [3][4][5]. Trp is one of the basic constituents of protein and a requisite in human nutrition to establish and maintain a positive nitrogen balance [6].…”

Colorimetric and fluorescence recognition of tryptophan and histidine using phthalaldehyde based probe: experimental, computational, cell imaging and fish tissue analysis

“…Recently uorescence sensing has become popular for operational simplicity, quick response time, non destructive methodology, high sensitivity and low operational cost. [10][11][12] Highly reactive imidazole unit of L-His allows it to involve in metallo-proteins and catalytic sites in certain enzymes. 9 L-Trp is vital in protein biosynthesis and serves as the precursor for various biomolecules, viz.…”

“…Thus, Trp content is closely related to the neurobehavioral effect like, appetite, sleeping-waking-rhythm, impulsivity, aggression, sexual behavior, and pain perception, HIV infections, cancers, Alzheimer's and Parkinson's disease. [10][11][12] Highly reactive imidazole unit of L-His allows it to involve in metallo-proteins and catalytic sites in certain enzymes. L-His is essential for growth and repair of human tissues and transmission of metal ions to biological bases.…”