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Redox polymers for electrocatalytic oxidation of NADH – Cationic styrene and ethylenimine polymers
Author(s) -
Huan Zhengwei,
Persson Bjórn,
Gorton Lo,
Sahni Suresh,
Skotheim Terje,
Bartlett Philip
Publication year - 1996
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.1140080614
Subject(s) - cationic polymerization , redox , polymer , styrene , chemistry , electrocatalyst , polymer chemistry , electrochemistry , inorganic chemistry , copolymer , organic chemistry , electrode
The electrocatalytic oxidation of nicotinamide adenine dinucleotide (NADH) by two redox polymers was evaluated from steady‐state measurements at drop‐coated solid graphite electrodes in 0.25 M phosphate buffer, pH 7.0, at 0 mV (vs. SCE). The redox polymers studied comprised a styrene polymer incorporating positive charges through quaternary amines and Toluidine Blue 0 (TBO) moieties (ST) and a branched polyethylenimine with part of its primary amine groups loaded with TBO (PE). The catalytic efficiencyjudged from the maximum NADH sensitivity for the PE polymer was estimated to be 230 μa cm. −2 mM −1 at a coverage of 40 μgcm −2 and for the ST polymer 300 μAcm −2 cmM −1 at about 100 μg cm −2 . Reagentless biosensors sensing D ‐glucose and L ‐malate were constructed from bulk modified carbon paste containing the PE redox polymer, NAD + , polyethylenimine (PEI) and D ‐glucose dehydrogenase or L ‐malate dehydrogenase. The D ‐glucose and L ‐malate sensors were characterized in a flow injection system by apparent j ′ max− and K ′ M ‐values of 230 μA cm −2 and 62mM and 3.3 μAcm −2 and 1.7mM, respectively. It was shown for glucose dehydrogenase that the presence of PEI in the paste in addition to the PE polymer, drastically improved the enzymatic conversion of glucose to gluconic acid.