Amperometric urea sensor based on urease and metal catalysts
- Resource Type
- Dissertation/ Thesis
- Authors
- 오호 / WU HAO
- Source
- Subject
- biosensor
urease
metal catalyst
- Language
- English
An amperometric biosensor based on binary metal catalysts (Pt and Rh) and multiwalled carbon nanotubes (MWCNTs) has been synthesized on indium tin oxide coated glass slides (ITO/Glass) for efficient electroanalytical detection of urea. Urease (Urs) enzyme was physically immobilized over the surface of the hybrid matrix (Pt-Rh/MWCNTs/ITO) and then entrapped with a polyion complex. The activity of the free and immobilized enzyme for urea hydrolysis and the metal catalysts for electrochemical oxidation of ammonia was investigated. The electrochemical performance of the bioelectrode was characterized by cyclic voltammetry technique. The sensor showed a linear amperometric response to urea concentration ranging from of 0 mM to 20 mM, with a linearity correlation coefficient of 0.994. A sensitivity of 1.7 µA•mM−1cm−2 and a response time of approximately 20 s was achieved for the hybrid electrode. The biosensor retains half of its initial activity after 20 days under ambient conditions. The urea sensor employing enzyme and binary metal catalysts exhibited an excellent electroactivity and sensor efficiency. Thus, the strategy developed in this study can be extended for a wide range of sensing applications.