Preparing of Iridium Oxide Film Modified Microelectrode as an Amperometric Detector in FIA for Determination of Epinephrine

Abstract

Iridium oxide film modified microelectrode with a tip diameter of 25 mm was constructed using anodically grown iridium oxide film. The iridium oxide film, which was formed at the tip of the iridium wire by cyclic voltammetry in dilute sulfuric acid, showed excellent catalytic activity towards the oxidation of epinephrine. The stability and electrochemical properties of iridium oxide film modified microelectrode along with catalytic oxidation of epinephrine was studied. An oxidation peak was observed at 0.28 V. The electron-transfer number (n) was 2. The iridium oxide film modified microelectrode was used as a detector in flow injection system for determination of epinephrine. Under the optimized conditions, the calibration curve was linear in the concentration range of 1.0 Â 10 28 to 1.0 Â 10 25 mol/l for epinephrine, with a detection limit of 1.0 Â 10 29 mol/l. The iridium oxide film modified microelectrode was used for direct determination of the epinephrine in human serum samples. The flow injection analysis was precise detection method of epinephrine and time saving device.

Double Modification of Electrode Surface for the Selective Detection of Epinephrine and Its Application to Flow Injection Amperometric Analysis

“…Many different molecules have been used to give electrocatalytic reaction of EP, which include penicillamine [22], caffeic acid [23], and homocysteine [24] SAMs (selfassembled monolayer). Inorganic materials such as iridium oxide [25] and mesoporous Al-incorporated SiO 2 [26] have also been used to promote electrochemical oxidation of EP. Lin et al [27] used gold nanoclusters and polypyrrole film to simultaneously determine EP and uric acid under coexistence of ascorbic acid through the electrodeposition of gold nanoclusters on the glassy carbon electrode (GCE) modified with overoxidized polypyrrole film.…”