Amperometric Determination of Urea Using Enzyme-Modified Carbon Paste Electrode

2004 Bulletin of the Korean Chemical Society (Print)  
An amperometric biosensor based on carbon paste electrodes (CPEs) for the determination of urea was constructed by enzyme (urease/GL-DH)-modified method. Urea was hydrolyzed to NH 4 + by catalyzing urease onto the enzyme-modified electrode surface in sample solution. In the presence of α-ketoglutarate and reduced nicotinamide adenine dinucleotide(NADH), a liberated NH 4 + produce to L-glutamate and NAD + by Lglutamate dehydrogenase (GL-DH). After the chemical reaction was proceeded, the
more » ... hemical reaction was occurred that an excess of the NADH was oxidized to NAD + . The oxidation current of NADH was monitored at +1.10 volt vs. Ag/AgCl. An optimum conditions of biosensor were investigated: The optimum pH range for catalyzed hydrolysis reaction of urea was pH 7.0-7.4. The linear response range and detection limit were 2.0 × 10 −5~2 .0 × 10 −4 M and 5.0 × 10 −6 M, respectively. Another physiological species did not interfere, except L-ascorbic acid.
doi:10.5012/bkcs.2004.25.10.1499 fatcat:eewpeyw2mrdflcdoeddm52ufnq