Improvement of the performance of H2O2 oxidation at low working potential by incorporating TTF-TCNQ into a platinum wire electrode for glucose determination.
A micro-biosensor was constructed by incorporating the organic conducting salt tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) into a platinized platinum (Pt) wire and further covering with the electrochemical polymerical heteropolypyrrole film, in which glucose oxidase (GOx) was entrapped. The enzyme electrode can sensitively determine glucose at a low working potential, mainly based on the oxidation of H2O2. The incorporated TTF-TCNQ can significantly improve the oxidation of H2O2 on the electrode, although a part of the TTF-TCNQ functions as a mediator. Compared with the same electrode prepared without TTF-TCNQ incorporated, the TTF-TCNQ modified electrode had better performance characteristics at a working potential of 200 mV (versus SCE). The response time to 90% of the steady value was shortened from about 40 s to less than 10 s, the lower limit of the linear response was greatly extended from about 1.6 mM to 10 microM, the linear range was shifted from 1.6-10.0 to 0.01-5 mM and the sensitivity was increased from about 1 to 1.5 microA/mM. The electrode was quite stable. For continuous operation, the electrode could work for about 5 weeks and only lost 60% of its original sensitivity. Stored at 4 degrees C for intermittent determinations, the electrode kept 80% sensitivity for over 6 months. Due to covering the electrode with a non-conductive heteropolypyrrole film, ascorbate, urate and 4-acetamidophenol caused only negligible current response at an applied potential of 200 mV.
Li
Q S
QS
State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China.
Ye
B C
BC
Liu
B X
BX
Zhong
J J
JJ
D015374:Biosensing Techniques; D004563:Electrochemistry; D004566:Electrodes; D004579:Electron Transport; D004795:Enzyme Stability; D005947:Glucose / Q000032:analysis*; D005949:Glucose Oxidase; D006571:Heterocyclic Compounds; D006861:Hydrogen Peroxide / Q000737:chemistry*; D007202:Indicators and Reagents; D009570:Nitriles; D010084:Oxidation-Reduction; D010100:Oxygen / Q000494:pharmacology
D006571:Heterocyclic Compounds; D007202:Indicators and Reagents; D009570:Nitriles; C013703:tetracyanoquinodimethane; D006861:Hydrogen Peroxide; D005949:Glucose Oxidase; C063887:tetrathiafulvalene; D005947:Glucose; D010100:Oxygen