Amperometric Urea Biosensor Using Aminated Glassy Carbon Electrode Covered with Urease Immobilized Carbon Sheet,Based on the Electrode Oxidation of Carbamic Acid |
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| Authors: | Xiuyun Wang Hiroaki Watanabe Naoyuki Sekioka Hiroshi Hamana Shunichi Uchiyama |
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| Affiliation: | 1. Department of Materials Science and Engineering, Graduate School of Engineering, Saitama Institute of Technology, 1690 Fusaiji Fukaya, Saitama 369‐0293, Japan;2. Liaoning University of Science and Technology,185 Qianshan Zhong Road, Anshan, Liaoning, China;3. Department of Applied Chemistry, Faculty of Engineering, Saitama Institute of Technology, 1690 Fusaiji, Fukaya, Saitama 369‐0294, Japan |
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| Abstract: | A large oxidation current can be observed when ammonium carbamate aqueous solution is electrolyzed using a glassy carbon electrode (GCE) at a potential exceeding 1.0 V vs. Ag/AgCl and amino groups are introduced at the surface of the GCE. Aminated GCE exhibits the electrocatalytic activity of the oxidation of ammonium carbamate that is produced from urea as an intermediate product of urease reaction, and a distinct oxidation current is observed when the aminated GCE is used to oxidize the urea in the urease solution. A novel amperometric determination method to detect urea has been developed. This method is based on the electrooxidation of carbamic acid produced during urease reactions. Urease is immobilized to polymaleimidostyrene (PMS) coated on the insulated amorphous carbon sheet set on the aminated GCE surface. A good linear relationship is observed between urea concentration and the electrolytic current of the urease‐immobilized electrode in the concentration range from 0.5 mM to 21.0 mM. The proposed urea biosensor has an effective merit in that the interference resulting from ammonia and pH change caused by the urease reaction can be eliminated, differing from conventional urea biosensors. |
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| Keywords: | Urea sensor Aminated glassy carbon electrode Detection of carbamic acid Polymaleimidostyrene Urease |
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