Abstract
The authors describe the synthesis of a nanocomposite consisting of graphene oxide, cobalt(III) oxide and horseradish peroxidase (HRP/GO-Co
3
O
4
) in a nafion matrix. The composite, when deposited on a glassy carbon electrode (GCE), is shown to enable electrochemical sensing of H
2
O
2
. The morphology of the nanocomposite was characterized by field emission scanning electron microscopy, X-ray diffraction spectroscopy, energy dispersive X-ray spectroscopy, UV-vis spectroscopy, and FTIR spectroscopy. The response of the modified electrode to H
2
O
2
was examined by cyclic voltammetry and DC potential amperometry at a working potential −0.57 V (vs. Ag/AgCl) at pH 7.0. Features include (a) a sensitivity of −18.7 ± 0.5 μA mM
−1
cm
−2
, (b) a linear dynamic range from 1 mM to 30 mM, (c) a 2 mM detection limit, and (d) a response time of ~20 s. The performance of the sensor for the routine analysis was investigated by the determination of H
2
O
2
present in hair dye product with appreciable percent recovery value. Moreover, the HRP/GO-Co
3
O
4
-nafion/GCE biosensor exhibited good selectivity towards H
2
O
2
quantification in presence of common interfering species such as glucose, uric acid and ascorbic acid. This good analytical performance makes this biosensor a promising tool for sensing of H
2
O
2
.
Graphical abstract
A nanocomposite consisting of graphene oxide, cobalt(III) oxide and horseradish peroxidase was applied in an electrochemical sensor of H
2
O
2
. The sensor showed high sensitivity, −18.7 ± 0.5 μA mM
−1
cm
−2
, a 2 mM detection limit, and a response time of ~20 s.