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Abstract
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This study introduces a new surface-renewable electrode
based on a sol–gel derived graphene ceramic composite.
The electrode was prepared by dispersing graphene nanosheets
into a solution of the sol–gel precursors containing methyl
triethoxysilane in methanol and hydrochloric acid. During
hydrolysis of methyl triethoxysilane, the graphene nanosheets
are trapped in the gel. After moulding and drying the composite,
it can be used as a surface-renewable electrode to which we
refer as a graphene ceramic composite electrode (GCCE).
Cyclic voltammograms of the hexacyanoferrate(II/III) model
redox system at the GCCE were compared to those obtained
with a conventional carbon ceramic electrode and showed a
highly improved electron transfer rate at the GCCE. The electrocatalytic
oxidation of ascorbic acid as a model analyte was
then studied at working potential of 50 mV and over the
3–84 μM concentration range. It revealed a sensitivity of
6.06 μA μM−1 cm−2 and a detection limit of 0.82 μM. The
GCCE was successfully applied to the determination of ascorbic
acid in orange juice and urine samples. Advantages such as
good mechanical and chemical stability, ease of fabrication,
and reproducible preparation make the GCCE a potentially
useful and widely applicable renewable electrode for use in
routine analysis.
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