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Optimization of acetylcholinesterase immobilization on microelectrodes based on nitrophenyl diazonium for sensitive organophosphate insecticides detection

Domenii publicaţii > Chimie + Tipuri publicaţii > Articol în revistã ştiinţificã

Autori: O.I.Covaci, B.Bucur, M.P.Bucur, G.L.Radu

Editorial: Springer, Microchimica Acta, 169, p.335-343, 2010.

Rezumat:

The immobilization of acetylcholinesterase on platinummicroelectrodes
modified with p-nitrobenzenediazonium
is optimized. In the first step, a layer of p-nitrophenyl groups
was deposited on the surface and then reduced to paminophenyl
groups. Finally, the enzyme was linked to the
amino groups on the surface using glutaraldehyde. Each step
of the electrode modification was characterized by cyclic
voltammetry and electrochemical impedance spectroscopy
(EIS) at acidic and neutral pH to modify the electric charges
of different bound moieties. The deposition of diazonium
groups was attempted by potentiometry, amperometry or CV,
but only potentiometry proceeded without passivation of the
surface. The use of microelectrodes improved the limit of
detection of ethylparaoxon measurements to 20 nM(compared
to 100 nM in case of screen-printed electrodes based on the
same method of immobilization). The method allowed the
production of stable and reproducible amperometric microbiosensors
and may be adapted to other enzymes and electrode materials

Cuvinte cheie: Microelectrod, Sare de diazoniu, Imobilizare enzima, microbiosenzor enzimatic // Microelectrode, Diazonium salt, Enzyme immobilization, Enzymatic microbiosensor

URL: http://doi:10.1007/s00604-010-0336-y