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Abstract
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The authors describe a non-enzymatic amperometric
sensor for glucose that was prepared by electrodeposition of
cobalt oxide nanoparticles on a graphene paste that is readily
obtained bymixing reduced graphene oxide (r-GO) nanosheets
and mineral oil in a mortar. An electrode was prepared and
characterized by cyclic voltammetry and electrochemical impedance
spectroscopy. Cobalt oxide nanoparticles were electrochemically
deposited on the electrode, and their morphology
was characterized by field emission scanning electron microscopy.
Cyclic voltammetric and chronoamperometric studies
showed the modified electrode to display electrocatalytic
activity toward the direct oxidation of glucose, best at a working
potential of 0.45 V (vs. SCE) in 0.1MNaOH solution. The
sensor exhibits a linear response in the 40 to 4000 μMglucose
concentration range, has a detection limit as low as 1.4 μM (at
an S/N ratio of 3), and a sensitivity of 1.21 μA μM−1 cm−2.
The electrode was successfully applied to the determination of
glucose in (spiked) human serum where it showed recoveries
between 97.2 and 103.4 %.
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