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Novel Protocol for Covalent Immobilization of Horseradish Peroxidase on Gold Electrode Surface
Author(s) -
Radi AbdElgawad,
MuñozBerbel Xavier,
CortinaPuig Montserrat,
Marty JeanLouis
Publication year - 2009
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.200804466
Subject(s) - horseradish peroxidase , chemistry , biosensor , covalent bond , hydrogen peroxide , electrochemistry , amperometry , amine gas treating , diazonium compounds , aqueous solution , combinatorial chemistry , diazo , inorganic chemistry , detection limit , nuclear chemistry , electrode , organic chemistry , chromatography , biochemistry , enzyme
A novel protocol for immobilization of horseradish peroxidase (HRP) onto diazonium functionalized screen‐printed gold electrode (SPGE) has been successfully developed. This protocol involved 1) electrochemical reduction of p ‐nitrophenyl diazonium salts synthesized in situ in acidic aqueous solution to graft a layer of p ‐nitrophenyl on SPGE, 2) electrochemical reduction of the nitro groups to convert to amines, 3) chemical reaction with nitrous acid to transform the amine to diazonium derivative and 4) chemical coupling of the enzyme with the diazonium group to form a covalent diazo bond. The fabricated biosensor showed the direct electrochemistry of HRP and displayed electrocatalytic activity towards the reduction of hydrogen peroxide (H 2 O 2 ) without any mediator. The biosensor exhibited fast amperometric response to H 2 O 2 . The catalytic current increased with increasing H 2 O 2 concentration from 5 μM to 30 μM and the detection limit of the biosensor was 2 μM. The biosensor exhibited acceptable sensitivity, good reproducibility and long‐term stability.