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Author(s) |
Nalini, S.; Nandini, S.; Shanmugam, S.; Neelagund, S. E.; Melo, J. S.; Suresh, G. S. (NA&BTD)
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Source |
Journal of Solid State Electrochemistry, 2014. Vol. 18 (3): pp. 685-701 |
ABSTRACT
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Novel
flower-like silver particles with triangular plates as building block
along with functionalized graphene (straggled sheets) and enzymes
horseradish peroxidase (HRP) or cholesterol oxidase (ChOx), were
obtained on graphite electrode by galvanostatic electrodeposition
method. The morphology of the electrodeposits has been characterized
using scanning electron microscopy and energy-dispersive analysis of
X-ray. The resulting biosensors named Nf/(HRPf - graphene-Ag)/Gr and
Nf/(ChOx-f-graphene-Ag)/Gr were evaluated for electrochemical activity
using cyclic voltammetry (CV), differential pulse voltammetry (DPV) and
chronoamperometry. Optimization of the interdependent experimental
parameters such as pH and temperature were achieved and maintained
constant throughout the experiments. An activation energy of 2.5 kJ mol−1
was obtained for Nf/(HRP-f-graphene-Ag)/Gr electrode while
Nf/(ChOx-fgraphene- Ag)/Gr showed an activation energy of 2.06 and 3.12
kJ mol−1. Furthermore, the former electrode demonstrated a
good linear range of 25 μMto 19.35mMwith rapid response time of 3 s and
detection limit of 5 μM for hydrogen peroxide. Similarly, the
Nf/(ChOx-f-graphene-Ag)/Gr electrode revealed a linear range of 0.1–4.5
mM with rapid response time of 3 s and an excellent detection limit of
0.514 mM for cholesterol. Besides this, the Nf/(HRP-f-graphene-Ag)/Gr
and Nf (ChOx-fgraphene- Ag)/Gr electrodes displayed a Michaelis–Menten
constant of 0.26 and 0.57 mM, respectively, suggesting high affinity and
enzymatic activity. The enhanced performance of biosensors towards
detection of substrate and rejection of interferents, provided an
evidence for its high antiinterference ability. Additionally the
biosensors exhibit long term storage stability and reproducibility with
antifouling properties. |
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