Electrode Material Containing Graphite Incorporated to an Amino-Functionalized Polydimethylsiloxane Network for the Detection of Copper

Ricardo Silva,Alzira Lucho,Fabio Pissetti

doi:10.21577/0103-5053.20180052

Abstract

Graphite was incorporated to a polydimethylsiloxane (PDMS) polymer network functionalized with amino groups to obtain an electrode material and used to detect copper ions in aqueous solutions and sugarcane spirit. The polymer network was prepared with PDMS, 3-aminopropyl-trimethoxysilane (APTMS), tetraethyl orthosilicate (TEOS) with addition of graphite to obtain the electrode material. The materials were prepared with different mass concentrations of PDMS: 0, 3, 6, 12 and 18%; and characterized by thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR). Quasi-reversible behavior was found when studying the [Fe(CN)6]3-/4- redox probe and were electrochemically stable up to 100 consecutive cycles. Electrochemical impedance measurements showed a second time constant at high frequencies for the PDMS electrodes, indicating a second phase in the polymer network with resistive properties, probably due to an increase in the material polymerization resistance. Square wave voltammetry studies were conducted with these electrodes to detect copper(II) ions in aqueous solution. The electrode proposed was applied to determine Cu2+ in a real sample, sugarcane spirit. The PDMS electrodes prepared here presented a potential to be applied as electrochemical sensors for detecting copper ions.

Highlights

Modified electrodes (CME) are made by adding chemically active species to the surface of an electrode substrate for the purpose of pre-establishing and controlling the physicochemical nature of the electrode/ solution interface
Formation of the organic-inorganic hybrid material occurred through hydrolysis of the tetraethyl orthosilicate (TEOS) and APTMS groups, which produced silanol-type reactive groups
The results suggest that electron transfer at the electrode/solution interface with the redox probe K3Fe(CN)[6] is controlled by diffusion of the probe ions in solution

Summary

Introduction

Modified electrodes (CME) are made by adding chemically active species to the surface of an electrode substrate for the purpose of pre-establishing and controlling the physicochemical nature of the electrode/ solution interface. The modification of an electrode normally gives the physicochemical characteristics (reactivity, selectivity, etc.) of the modifier. This enables the development of devices with suitable responses for many purposes and applications.[1]. An important aspect in the preparation of a CME is the choice of the electrode base material that will have its surface modified This substrate should have appropriate electrochemical characteristics and be compatible with the chosen modification method, among the conventionally used materials are: gold, platinum, vitreous carbon and carbon paste.[2] As an example, a modified carbon paste electrode can be made by the addition of different classes of chemical compounds to a mix of graphite powder and an agglutinative agent.[3,4,5]

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