GRAPHENE NANOCOMPOSITE MODIFIED ELECTRODE FOR ELECTROCHEMICAL DETECTION

Abstract

The electrochemical sensors based on graphene nanocomposite modified screen-printed carbon electrode (SPCE) were prepared for the determination of target analytes (e.g. cholesterol, hydrazine). This study is separated into two main parts. The first one is using graphene-polyvinylpyrrolidone/polyaniline nanocomposite (G-PVP/PANI) modified SPCE for the determination of cholesterol. The second one is development of nitrogen-doped graphene-polyvinylpyrrolidone/gold nanoparticles (NG-PVP/AuNPs) modified SPCE as a novel electrochemical sensor for hydrazine. The factors affecting the electrochemical sensitivity of the systems, such as electrode composition and electrochemical parameters were evaluated. Scanning electron microscopy and transmission electron microscopy were used for physical characterization of modified SPCE. The electrochemical behaviors of the modified SPCE were examined by cyclic voltammetry and electrochemical impedance spectroscopy. The modified SPCEs showed the improved electrochemical sensitivities compared to unmodified SPCE. Under optimum conditions, the modified SPCEs exhibited a low detection limit, a high sensitivity and a wide linearity. Moreover, the selectivity of modified SPCEs in the presence of common interferences was investigated. Ultimately, the modified SPCEs were successfully applied for the sensitive determination of target analytes in real samples.