title: The potential use of hydrazine as an alternative to peroxidase in a biosensor: comparison between hydrazine and HRP-based glucose sensors.
abstract: The potential use of hydrazine sulfate was examined for the catalytic reduction of enzymatically generated H2O2 in a biosensor system. The performance of the hydrazine-based sensor was compared with an HRP-based glucose sensor as a model of a biosensor. Hydrazine and HRP were covalently immobilized onto a conducting polymer layer with glucose oxidase. The direct electron transfer reactions of the immobilized hydrazine and HRP onto the poly-5,2':5,2''-terthiophene-3'-carboxylic acid (poly-TTCA) layer were investigated by using cyclic voltammetric method and the electron transfer rate constants were determined. The glucose oxidase- and hydrazine-immobilized sensor efficiently reduced the enzymatically generated H2O2 at -0.15 V versus Ag/AgCl. The surface of this GOx/hydrazine/poly-TTCA-based glucose sensor was characterized by QCM, SEM, and ESCA. Glucose-sensing properties were studied using cyclic voltammetric and chronoamperometric techniques. Various experimental parameters were optimized according to the amount of hydrazine, pH, the temperature, and the applied potential. A linear calibration plot was obtained in the concentration range between 0.1 and 15.0 mM, and the detection limit was determined to be 40.0+/-7.0 microM. Interferences from other biological compounds were studied. The long-term stability of the GOx/hydrazine sensor was better than that of the one based on a GOx/HRP biosensor. The proposed glucose sensor was successfully applied to human whole blood and urine samples for the detection of glucose.
authors: Department of Chemistry and Center for Innovative Bio-Physio Sensor Technology, Pusan National University, Busan 609-735, South Korea.
authors: Md Aminur
authors: MA
authors: Rahman
authors: Mi-Sook
authors: MS
authors: Won
authors: Yoon-Bo
authors: YB
authors: Shim
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D020099:Coated Materials, Biocompatible / Q000032:analysis / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000032:analysis / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D005947:Glucose / Q000032:analysis* / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000032:analysis / Q000737:chemistry*; D006834:Hydrazines / Q000032:analysis / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013499:Surface Properties
chemical_list: D020099:Coated Materials, Biocompatible; D004800:Enzymes, Immobilized; D006834:Hydrazines; C029424:hydrazine; D006735:Horseradish Peroxidase; D005947:Glucose