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Stabilization of an osmium bis‐bipyridyl polymer‐modified carbon paste amperometric glucose biosensor using polyethyleneimine
Author(s) -
Jezkova Jitka,
Iwuoha Emmanuel I.,
Smyth Malcolm R.,
Vytras Karel
Publication year - 1997
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.1140091303
Subject(s) - amperometry , glucose oxidase , biosensor , carbon paste electrode , redox , chemistry , electrode , polymer , cyclic voltammetry , electrochemistry , nuclear chemistry , osmium , inorganic chemistry , organic chemistry , biochemistry , catalysis , ruthenium
The modification of carbon paste electrodes by incorporation of the enzyme glucose oxidase (GOx) and a conducting redox osmium bis‐bipyridyl poly(4‐vinylpyridine) polymer (Os‐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 Os‐polymer containing Os 2+/3+ redox couple mediated the electron transfer from reduced GOx to the carbon paste electrode material. Steady‐state amperometric responses of the sensors to 2–120 mM glucose at an operating potential of 350 mV (vs. Ag/AgCl) were determined in 0.1 M phosphate buffer (pH 7.0) 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 ′ cat showed that PEI decreases the diffusion limitations of CPE, thereby increasing the frequency of collision of reacting species in this biosensor format.