Stabilization of an osmium bis-bipyridyl polymer-modified carbon paste amperometric glucose biosensor using polyethyleneimine
✍ Scribed by Jitka Jezkova; Emmanuel I. Iwuoha; Malcolm R. Smyth; Karel Vytras
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 754 KB
- Volume
- 9
- Category
- Article
- ISSN
- 1040-0397
No coin nor oath required. For personal study only.
✦ Synopsis
The modification of carbon paste electrodes by incorporation of the enzyme glucose oxidase (GOx) and a conducting redox osmium his-bipyridyl poly(4-vinylpyridine) polymer (0s-polymer) is described. The resulting enzyme electrodes were operated as amperometric glucose sensors in the presence or absence of a stabilizer, polyethyleneimine (PEI), mixed into the paste. Cyclic voltammetric studies showed that 0s-polymer containing redox couple mediated the electron transfer from reduced GOx to the carbon paste electrode material. Steady-state amperometric responses
of the sensors to 2-120mM glucose at an operating potential of 350mV (vs. AglAgCI) were determined in 0.1 M phosphate buffer (pH7.0) medium. The study showed that PEI enhances both, the sensitivity and stability of the carbon paste enzyme electrode and that a diffusion-limited step precedes electrocatalytic reactions of the biosensor. Cyclic voltammetric data and the Arrhenius analysis of the apparent turnover rate constant, k:,,, showed that PEI decreases the diffusion limitations of CPE, thereby increasing the frequency of collision of reacting species in this biosensor format.