title: Amperometric urea biosensor based on urease and electropolymerized toluidine blue dye as a pH-sensitive redox probe.
abstract: The electropolymerized toluidine blue film deposited on the glassy carbon electrode show amperometrically detectable pH sensitivity. This feature of polytoluidine blue (PTOB) film was used for a construction of an amperometric urea biosensor. We have observed a linear shift of the formal redox potential with increasing pH value between 4 and 8 giving the slope of 81 mV(Delta) pH(-1). Polytoluidine blue film has had a significantly increased stability and higher electrochemical activity compared to the adsorbed monomeric dye. The polytoluidine blue urea biosensor has been operating at a working potential of -200 mV vs. SCE. The sensitivity of the biosensor was 980 nA mM(-1) cm(-2). The biosensor showed linearity in concentration range up to 0.8 mM with the detection limit of 0.02 mM (S/N=3).
authors: Department of Biochemical Technology, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinskeho 9, SK-812 37 Bratislava, Slovak Republic. vostiar@chelin.chtf.stuba.sk
authors: Igor
authors: I
authors: Vostiar
authors: Jan
authors: J
authors: Tkac
authors: Ernest
authors: E
authors: Sturdik
authors: Peter
authors: P
authors: Gemeiner
mesh_terms: D015374:Biosensing Techniques; D004563:Electrochemistry / Q000295:instrumentation*; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D011108:Polymers; D012680:Sensitivity and Specificity; D014048:Tolonium Chloride / Q000737:chemistry*; D014508:Urea / Q000737:chemistry*
chemical_list: D011108:Polymers; D014048:Tolonium Chloride; D014508:Urea