Graphene quantum dot functionalized by beta-cyclodextrin: a novel nanocomposite toward amplification of l-cysteine electro-oxidation signals

Nasrin Shadjou,Mohammad Hasanzadeh,Faeze Talebi,Ahmad Poursattar Marjani

doi:10.1080/20550324.2016.1187428

Nasrin Shadjou, Mohammad Hasanzadeh + Show 2 more

Open Access

https://doi.org/10.1080/20550324.2016.1187428

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Abstract

A novel nano-composite of graphene quantum dot-β-cyclodextrin was fabricated on the surface of glassy carbon electrode (GCE) using one step and green electrodeposition method. The redox of l-Cys behavior prepared nano-composite-modified of GCE was then characterized by cyclic voltammetry, chronoamperometry, and differential pulse voltammetry. Voltammograms of the modified electrode are recorded in physiological pH (phosphate buffer solution, pH 7.4), the kinetics of charge transfer and mass transport processes across the nano-composite/solution interface were studied. The modified electrode showed an efficient electrocatalytic activity toward the oxidation of l-Cysteine (l-Cys) through a surface-mediated electron transfer. The catalytic rate constant and the l-Cys diffusion coefficient were reported. A sensitive and time-saving method (differential pulse voltammetry) was developed for the analysis of l-Cys. The proposed voltammetric method was also applied to the determination of l-Cys using graphene quantum dot-β-cyclodextrin-GCE.

Highlights

Introduction lCysteine (l-Cys) belongs to sulfur-containing amino acid molecules playing a crucial role in biological systems and food industries.[1,2,3] l-Cys can be used for the clinical diagnosis of the disease states
A novel nano-composite of graphene quantum dot-β-cyclodextrin was fabricated on the surface of glassy carbon electrode (GCE) using one step and green electrodeposition method
An irreversible cyclic voltammetry (CV) peaks were observed from CVs of l-Cys at different modified GCEs (GQD-GCE and β-CD-graphene quantum dots (GQDs)-GCE)

Summary

Introduction

Introduction lCysteine (l-Cys) belongs to sulfur-containing amino acid molecules playing a crucial role in biological systems and food industries.[1,2,3] l-Cys can be used for the clinical diagnosis of the disease states. By the comparison with other methods, electrochemical method takes inherent advantages of simple operation, high sensitivity, low cost, good selectivity, easy miniaturization and in vivo real time. It is necessary to explore novel electrode materials to improve the electrochemical performance for the determination of l-Cys

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