Amperometric thiol sensor based on Prussian blue-modified glassy carbon electrode q A.K.M. Kafi a , Fan Yin a,b , Hoon-Kyu Shin a , Young-Soo Kwon a, * a Department of Electrical Engineering and CIIPMS, Dong-A University 840, Hadan-2dong, Saha-gu, Busan 604-714, Republic of Korea b Department of Chemistry, Changshu Institute of Technology, Changshu 215500, China Received 13 May 2006 Available online 4 December 2006 Abstract This paper describes the performance of an amperometric sensor for thiol detection. The sensor was designed based on a Prussian blue (PB) glassy carbon (GC) electrode. Prussian blue was chemically deposited onto the glassy carbon electrode by a dropletting method. Thiol compounds were detected at the PB-modified GC electrode by electrooxidation. A PB-modified glassy carbon electrode was applied to detect thiol at an applied potential of +0.25 V versus the Ag/AgCl electrode. This sensor showed an excellent electrochemical response for thiol compounds below lmol level with high sensitivity and selectivity and short response time. In the case of aminoetha- nethiol, the sensor showed a wide linearity range with RSDs <4% for the whole analyses, which reflected the highly reproducible sensor performance. The optimal conditions were investigated. By using the optimized conditions, the detection limit was found to 0.4 lM for aminoethanethiol (based on S/N = 3). Ó 2006 Elsevier B.V. All rights reserved. PACS: 07.07.Df Keywords: Prussian blue; Thiol compound; Sensor 1. Introduction Chemically modified electrodes have useful applications in the electrochemical and bioelectrochemical science area. These kinds of modified electrodes have been used success- fully in the areas of amperometry [1], electrochemical activ- ity [2,3], electrocatalysis [4], etc. (PB) Prussian blue Fe[Fe 3+ Fe 2+ (CN) 6 ] 3 is widely used to manufacture electro- chemical senor, biosensor [5], etc. due to its’ well known redox characteristic [6]. In this aspect Itaya and Shibayama [7] discussed a method for the preparation of PB-modified electrodes based on simple reduction of a ferric-ferricya- nide solution. The structure of Prussian blue is an interest- ing subject of investigation in order to explain its catalytic activity towards many compounds and electrochemical properties. Few different types of chemically or electro- chemically modified electrodes modified by PB have been reported. Some reports have published mentioning Prus- sian blue- and hexacyanoferrate-modified glassy carbon electrodes [8]. Electrocatalytic oxidation of the thio com- pound by metal hexacyanoferrate has also been reported [8]. Thio compounds have an important role in chemical, biological and pharmacological processes. Nowadays, there are many research groups are paying their attention to the electrochemical detection of thiol compounds. Therefore, the main target this work was the electrochem- ically determination of thiol compounds by a PB-modified GC electrode. To the best of our knowledge, this is the first time a chemical sensor with PB for thiol detection has been designed. The proposed sensor showed quick response to the thiol compound and long-term stability. 1567-1739/$ - see front matter Ó 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.cap.2006.10.004 q Part of this work has been presented during 16th ME&D Symposium held in Daejeon on May 12–13, 2005. * Corresponding author. Tel.: +82 51 200 7738; fax: +82 51 200 7743. E-mail address: yskwon@dau.ac.kr (Y.-S. Kwon). www.elsevier.com/locate/cap www.kps.or.kr Current Applied Physics 7 (2007) 496–499