Electrochemistry of Levo‐Thyroxin on Edge‐Plane Pyrolytic Graphite Electrode: Application to Sensitive Analytical Determinations |
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| Authors: | Mona Khafaji Saeed Shahrokhian Masoumeh Ghalkhani |
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| Institution: | 1. Department of Chemistry, Sharif University of Technology, Tehran 11155‐9516, Iran tel.: +98‐21‐66005718, fax: +98‐21‐66012983;2. Institute for Nanoscience and Technology, Sharif University of Technology, Tehran, Iran |
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| Abstract: | The electrochemical response of sodium levo‐thyroxin (T4) at the surface of an edge plane pyrolytic graphite (EPPG) electrode is investigated using cyclic voltammetric technique in the presence of 0.1 M HCl as supporting electrolyte. T4 underwent totally irreversible oxidation at this system and a well‐defined peak at 821 mV was obtained. Compared to the signals obtained in the optimized conditions at bare glassy carbon and carbon paste electrodes, the oxidation current of T4 at an EPPG electrode was greatly enhanced. The electrochemical process of T4 was explored and the experimental conditions were optimized. The oxidation peak current represented a linear dependence on T4 concentration from 0.01 to 10 µM. The detection limit of 3 nM (S/N=3) was obtained for 250 s accumulation at 0.3 V. Determination of T4 in a synthetic serum sample demonstrated that this sensor has good selectivity and high sensitivity. |
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| Keywords: | Levo‐thyroxine Edge plane pyrolytic graphite Cyclic voltammetry Analytical determination |
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