Biomolecules Electrochemical Sensing Properties of a PMo11V@N-Doped Few Layer Graphene Nanocomposite

Diana Fernandes,Cristina Freire,Pedro De Oliveira,Ricardo Carvalho,Israel-Martyr Mbomekalle,Philippe Serp,Marta Nunes,Revathi Bacsa

doi:10.3390/inorganics3020178

Abstract

A novel hybrid nanocomposite, PMo11V@N-doped few layer graphene, was prepared by a one-step protocol through direct immobilization of the tetrabutylammonium salt of a vanadium-substituted phosphomolybdate (PMo11V) onto N-doped few layer graphene (N-FLG). The nanocomposite characterization by FTIR and XPS confirmed its successful synthesis. Glassy carbon modified electrodes with PMo11V and PMo11V@N-FLG showed cyclic voltammograms consistent with surface-confined redox processes attributed to Mo-centred reductions (MoVI→MoV) and a vanadium reduction (VV→VIV). Furthermore, PMo11V@N-FLG modified electrodes showed good stability and well-resolved redox peaks with high current intensities. The observed enhancement of PMo11V electrochemical properties is a consequence of a strong electronic communication between the POM and the N-doped few layer graphene. Additionally, the electro-catalytic and sensing properties towards acetaminophen (AC) and theophylline (TP) were evaluated by voltammetric techniques using a glassy carbon electrode modified with PMo11V@N-FLG. Under the conditions used, the square wave voltammetric peak current increased linearly with AC concentration in the presence of TP, but showing two linear ranges: 1.2 × 10−6 to 1.2 × 10−4 and 1.2 × 10−4 to 4.8 × 10−4 mol dm−3, with different AC sensitivity values, 0.022 A/mol dm−3 and 0.035 A/mol dm−3, respectively (detection limit, DL = 7.5 × 10−7 mol dm−3).

Highlights

Taking advantage of the electroactivity of some drugs and biomolecules, the application of electrochemical sensors for biological analysis has been growing rapidly, mainly due to the simplicity, accuracy, precision, low cost and rapidity of the electrochemical techniques [1]
The tetra-butylammonium salt of the vanadium-phosphomolybdate, PMo11V was prepared according to the literature and characterized by several techniques [31] and the PMo11V@N-doped few layer graphene (N-FLG) was prepared using an adapted procedure [38]
The vanadium-substituted phosphomolybdate PMo11V was successfully immobilized on N-doped few layer graphene

Summary

Introduction

Taking advantage of the electroactivity of some drugs and biomolecules, the application of electrochemical sensors for biological analysis has been growing rapidly, mainly due to the simplicity, accuracy, precision, low cost and rapidity of the electrochemical techniques [1]. Nanostructured materials, in particular, carbon-based nanomaterials such as carbon nanotubes and graphene, have attracted considerable interest in this field, owing to their unique physical, chemical and electrochemical properties They present low residual current, readily renewable surfaces and wide potential windows, providing an important and feasible platform for electroanalysis [3,4]. Graphene (G), in particular, emerged as a “superstar” material in the last years, being characterized by a two-dimensional (2D), single-layer sheet of sp2-hybridized carbon atoms that are closely packed into a hexagonal lattice structure [5] Its properties, such as fast electron transportation, high thermal conductivity, excellent mechanical strength and high surface area, suggest its ability to detect analyte molecules and to promote a fast electron transfer between the electrode and the analyte, which make it a promising electrocatalyst [3,5]. Several reports published show the good sensitivity and electrocatalytic activity of pristine graphene and graphene-based nanocomposites on the electrochemical sensing of biomolecules such as dopamine (DA) [6,7], uric (UA) and ascorbic (AA) acids [8], nucleic acids [9] and glucose [10]

Methods

Results

Conclusion