Thermoplastic Starch and Graphite Biocomposite Electrode for Electrochemical Catechol Sensor

Abstract

There is interest in obtaining alternative materials for application in electrochemical sensing. Thermoplastic starch (TPS) was used because it is a polymer with high availability and biodegradability, which can be incorporated into graphite (Gr) forming a conductive material. This work describes the characterization of the material produced by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), contact angle, X-ray diffraction (XRD) and Raman spectroscopy. The techniques used allowed to show a good interaction between graphite and TPS and confirmed the predicted conductive properties, showing the potential of application as a substrate, in the development of electrochemical sensors. Electrochemical characterization by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) was also carried out, which allowed defining the best proportion of graphite:TPS as the composite of 60:40 w/w. The technique of differential pulse voltammetry (DPV) was used to determine the catechol molecule over a range of 0.1 to 2.0 mmol l−1, showing a linear regression (R2) of 0.9996 and limit of detection (LOD) and limit of quantitation (LOQ) values equal to 1.85 × 10−6 mol l−1 and 6.18 × 10−7 mol l−1, respectively. The results showed good precision, selectivity, and stability, proving the application as an electrochemical sensor to detect catechol (CC) in contaminated water.