Electrochemical Sensor for Epinephrine Based on a Glassy Carbon ElectrodeModified With Carbon Nanotubes/Ag (I) Complex

Epinephrine, also known as adrenaline, is primarily a medication and a hormone. As amedication it is used for a number of conditions including anaphylaxis, cardiac arrest, andsuperficial bleeding. Inhaled epinephrine may be used to improve the symptoms of croup. Itmay also be used for asthma when other treatments are not effective. It is given intravenously,by injection into a muscle, by inhalation, or by injection just under the skin. The common sideeffects of epinephrine include shakiness, anxiety, and sweating. A fast heart rate and high bloodpressure may occur. Occasionally it may result in an abnormal heart rhythm [1]. Therefore,determination of epinephrine is interesting for understanding the physiological functions.Electrochemical procedures have been developed to determine epinephrine based on thiselectrochemical activities. But electrochemical detection of epinephrine at the surface of bareelectrodes has a high overpotential, which results in weak electrochemical responses. To solvethis problem, various modified electrodes have been developed for the selective determinationof epinephrine [2]. Carbon nanotubes (CNTs) have been widely used in electrochemistry due totheir unique one-dimensional (1D) structural, electronic, and physical properties. In the field ofchemically modified electrode, one of the most important characteristics of CNTs is theirreported ability to promote electron-transfer process [3]. The CNT/Ag (I) complex modifiedglassy carbon electrode (CNT/Ag/GCE) exhibited high sensitivity in the detection ofepinephrine (scheme 1, Ag(I) complex). It has been found that oxidation of EP at this modifiedelectrode occurred at less positive potentials than on bare GCE. The anodic peak currentobserved were directly proportional to epinephrine concentration between the range of 5.0×10−8and 8.0×10−6 M (LOD = 7.0×10−9 M). At the same time, this electrode also showed favorableelectrocatalytic activity toward some other small biomolecules (such as dopamine, ascorbic acidand uric acid), suggesting the potential applications of CNT/Ag(I) complex for constructingbiosensors.

کلیدواژه ها:

Epinephrine ، Ag (I) complex ، Carbon nanotubes ، Glassy carbon electrode