Voltammetric Response of Epinephrine at Carbon Nanotube Modified Glassy Carbon Electrode and Activated Glassy Carbon Electrode

The electrochemical behavior of epinephrine at activated glassy carbon electrode and carbon nanotube-coated glassy carbon electrode was studied. Epinephrine could exhibit an anodic peak at about 0.2 V (vs. SCE) at bare glassy carbon electrode, but it was very small. However, when the electrode was activated at certain potential (i.e. 1.9 V) or modified with carbon nanotube, the peak became more sensitive, resulting from the increase in electrode area in addition to the electrostatic attraction. Under the selected conditions, the anodic peak current was linear to epinephrine concentration in the range of 3.3×10~-7-1.1×10~-5 mol/L at activated glassy carbon electrode and in the range of 1.0×10~-6-5.0×10~-5 mol/L at carbon nanotube-coated electrode. The correlation coefficients were 0.998 and 0.997, respectively. The determination limit was 1.0×10~-7 mol/L. The two electrodes have been successfully applied for the determination of epinephrine in adrenaline hydrochloride injection with recovery of 95%-104%.