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

摘要

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 (a) and the electrode reaction standard rate constant (k_s) 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.