Electrochemical oxidation of guanosine-5′-triphosphate on a graphene and ionic liquid composite modified carbon molecular wire electrode

A graphene, chitosan and 1-ethyl-3-methylimidazolium tetrafluoroborate composite was prepared and modified on the surface of a carbon molecular wire electrode. The fabricated electrode was characterized by different methods such as scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. Electrochemical behaviors of guanosine-5′-triphosphate (GTP) were carefully studied on the modified electrode. The electrochemical parameters such as the charge transfer coefficient (α) and the electrode reaction standard rate constant (ks) were calculated with the results as 0.57 and 1.56 × 10−4 s−1. Under the optimized conditions, the oxidation peak current was proportion to the GTP concentration in the range from 0.007 to 70.0 μmol/L with the detection limit of 0.232 nmol/L (S/N = 3). Moreover, the proposed method showed good selectivity to the GTP detection without the interference of coexisting substances, and was further applied to the artificial samples determination with satisfactory results.