An Electrochemical Glucose Biosensor Depending on ZnCo 2 O 4 /Co 3 O 4 Nevzat Kazak, Muhammet Guler
ABSTRACT
In the article, an electrochemical glucose biosensor depending upon the bonding of glucose oxidase enzyme (GOx) on zinc cobaltite (ZnCo 2 O 4 )/cobalt (II, III) oxide (Co 3 O 4 )/carboxylated graphene oxide (f‐GO) modified working electrode was constructed. The ZnCo 2 O 4 /Co 3 O 4 /f‐GO/GOx/GCE exhibited excellent electron transfer between the electrode and the enzyme. The success of the transfer between GOx and the electrode was demonstrated by the cyclic voltammogram, which showed two distinct, quasi‐reversible anodic and cathodic peaks with a peak‐to‐peak separation potential of 0.050 V. The biosensor showed a dynamic linear determination range from 2.0 × 10 −6 to 4.3 × 10 −3 M by means of amperometric method. The limit of detection (LOD) was estimated as 6.0 × 10 −7 M depending on signal to ratio ( S / N ) of three. The apparent Michaelis–Menten constant ( was computed to be 6.84 ± 0.63 mM. The ZnCo 2 O 4 /Co 3 O 4 /f‐GO/GOx/GCE had a sensitivity of 41.91 ± 0.60 µA mM −1 cm −2 . The biosensor displayed excellent selectivity, repeatability with relative standard deviation (RSD) between 0.70% and 2.12% and reproducibility with RSD between 1.06% and 5.23%. Finally, the biosensor exhibited outstanding potential for use in real samples in the practical application investigations.