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A biosensor for L‐amino acids using polytyramine for enzyme immobilization
Author(s) -
Cooper Julia C.,
Schuber Florian
Publication year - 1994
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.1140061107
Subject(s) - hydrogen peroxide , chemistry , amino acid , phenylalanine , analyte , detection limit , biosensor , amine gas treating , calibration curve , polymer , immobilized enzyme , electrode , combinatorial chemistry , chromatography , organic chemistry , enzyme , biochemistry
Electrodeposition of polytyramine is demonstrated to be a simple and convenient procedure for electrode modification, generating amine groups to which L‐amino acid oxides can be covalently bound. An L‐amind acid oxidase (L‐AAOD)‐polytyramine electrode can be used for detection of L amino acids, via the current due to oxidation of enzymatically produced hydrogen peroxide. The calibration graph of the sensor for phenylalanine is linear up to 1.4 mM with a lower limit of detection of 0.07 mM. The useful measuring range for leucine is between 0.07 and 3 mM. The enzyme‐polytyramine electrodes are stable for more than 1 month. The polymer coating affords some protection of the elearode from direct (nonenzymic) oxidation of electroctive amino acids, which may otherwise cause elecatrode fouling, although at present, the polymer selectivity is insufficient to prevent errors in estimation of analyte concentration.