Analysis of Adsorbing Molecules on Pt Surface Using Electrochemical Impedance Spectroscopy

Kenshi HAYASHI
Kosuke HAYAMA
Kumi MASUNAGA
Wataru FUTAGAMI
Seung-Woo LEE
Kiyoshi TOKO

Publication
IEICE TRANSACTIONS on Electronics   Vol.E87-C    No.12    pp.2087-2092
Publication Date: 2004/12/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Recent Progress in Organic Molecular Electronics)
Category: Bioelectronic and Sensor
Keyword: 
chemical sensor,  constant phase element,  electrochemical impedance,  surface analysis,  adsorption,  

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Summary: 
Chemical sensor which can be used for a multi-purpose chemical measurement to detect various chemical substances with a small number of a sensor array was investigated. It was confirmed that chemical compounds adsorbed strongly and irreversibly on a platinum surface using conventional electrochemical methods and an instrumental surface analysis. The adsorbates were also analyzed by means of an electrochemical impedance spectroscopy under dynamic potential scan; measured impedance reflects CPE (constant phase element) properties of the electrode surface. The method provides a convenient technique for the surface analysis of adsorbing chemicals. The CPE response profile was modified through chemical adsorption/desorption and the interaction between the polarized surface and chemical substances. Consequently, various profiles depending on chemical substances were obtained and it had quantitative and qualitative information about chemicals interacting with the surface. The present method which does not require a specific electrochemical reaction can be applied for multi-purpose chemical sensors and also simple chemical analyses.