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

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.