Fabrication of nano-ZnS coated PEDOT-reduced graphene oxide hybrids modified glassy carbon-rotating disk electrode and its application for simultaneous determination of adenine, guanine, and thymine

Abstract We proposed a facile approach for the synthesis of zinc sulfur-coated poly (3,4-ethylenedioxythiophene)-reduced graphene oxide hybrids film (ZnS-PEDOT-rGO) by using thioacetamide (TAA) as the reducing agent. The ZnS-PEDOT-rGO hybrids film modified glassy carbon-rotating disk electrode (GC-RDE) was then developed for the sensitive simultaneous determination of three deoxyribonucleic acid (DNA) bases: guanine (G), adenine (A), and thymine (T). By cyclic voltammetry (CV), this electrochemical sensor showed a good photoelectronic effect, and the peak currents of G, A, and T increased obviously. Some kinetic parameters were estimated by linear sweep voltammetry (LSV). Under the optimal conditions, the magnified anodic peak currents represented the excellent analytical performance of simultaneous detection of G, A, and T in a wide linear range and low detection limit. This proposed method also has been successfully applied to the assessment of G, A, and T contents in real-life samples, such as herring sperm DNA samples, milk powder and urine sample from human beings, with satisfactory results. The obtained results were also compared to HPLC of analysis for those three DNA bases and no significant differences were found. By the treatment of the experimental data, the electrochemical reaction mechanisms of G, A, and T all involved a two-electron-two-proton-transfer process.