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Microdialysis fiber enzyme electrode involving amplification by substrate recycling
Author(s) -
Yao Toshio,
Suzuki Seita,
Nishino Hirohito,
Nakahara Taketoshi
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.1140091217
Subject(s) - electrode , platinum , nad+ kinase , microdialysis , chemistry , hydrogen peroxide , lactate dehydrogenase , reference electrode , dehydrogenase , fiber , biosensor , clark electrode , inorganic chemistry , chromatography , nuclear chemistry , biochemistry , enzyme , extracellular , catalysis , electrochemistry , organic chemistry , electrolyte
A microdialysis fiber electrode involving amplification for the NAD + /NADH couple is described. The electrode contains glucose‐6‐phosphate dehydrogenase, lactate dehydrogenase and lactate oxidase held stationary within its cavity, with a platinum fiber coated with poly(1,2‐diaminobenzene) film as a working electrode and a silver/silver chloride fiber as a reference electrode. Both NAD + and NADH are recycled enzymatically in the presence of an excess of glucose‐6‐phosphate and pyruvate in the measuring buffer solution. As a result, a large amount of L‐lactate produced in the electrode cavity is converted to pyruvate to produce hydrogen peroxide, which can be detected ampero metrically at the platinum fiber with a size‐exclusion film. Both NAD + and NADH were detected with a 25‐fold increase in sensitivity compared with the unamplified responses. The detection limit was 1 × 10 −7 M.