Electrochemical Behaviors of Adenosine-5′-triphosphate on Molecular Wire Modified Carbon Paste Electrode and Its Sensitive Detection

A new electrochemical method was proposed for the determination of adenosine-5′-triphosphate (ATP) based on the electrooxidation at a molecular wire (MW) modified carbon paste electrode (CPE), which was fabricated with diphenylacetylene (DPA) as the binder. A single well-defined irreversible oxidation peak of ATP appeared on MW-CPE with adsorption-controlled process and enhanced electrochemical response in a pH 3.0 Britton-Robinson buffer solution, which was due to the presence of high conductive DPA in the electrode. The electrochemical parameters of ATP were calculated with the electron transfer coefficient (α) as 0.54, the electron transfer number ( n ) as 1.9, the apparent heterogeneous electron transfer rate constant ( k s ) as 2.67 × 10 −5 s −1 and the surface coverage (Γ T ) as 4.15 × 10 −10 mol cm −2 . Under the selected conditions the oxidation peak current was proportional to ATP concentration in the range from 1.0 × 10 −7 mol L −1 to 2.0 × 10 −3 mol L −1 with the detection limit as 1.28 × 10 −8 mol L −1 (3σ) by sensitive differential pulse voltammetry. The proposed method showed good selectivity without the interferences of coexisting substances and was successful applied to the ATP injection samples detection.