Electrochemical measurements
Linear sweep voltammogram to study the electrocatalytic activity of the modified electrodes is represented in Fig. 9.
The electrodes were scanned at 100 mv/s in presence of 5 mM D (+) glucose. There was no signal response detected for bare FTO (curve a). GO/FTO (curve b) and CuO/FTO (curve c) showed a small increase in background current due to the large superficial area of GO and electrocatalytic capability for glucose oxidation of CuO respectively. A well-defined glucose oxidation peak was observed for GO/CuO/FTO (curve d) in the presence of 5 mM glucose at + 0.6 V. This indicates that the GO/CuO/FTO composite electrode is necessary to obtain high sensitivity and better electrocatalytic activity.
During the oxidation process, CuO was oxidized to CuOOH and glucose to gluconolactone by Cu (III) (Wei H et al. 2009).
Further, the electrochemical effect on GO/CuO/FTO with a variable scan rate was examined using LSV as shown in Fig. 10. The electrode was scanned from 10 to 300 mv/s (a to h) in PBS electrolyte in the presence of 5 mM D (+) glucose. The oxidation occurred at + 0.6 V for each scan and the oxidation peak current was increased with an increase in scan rate. This revealed that electrochemical reaction takes place on GO/CuO nanocomposite demonstrating its ability towards enzyme sensing (Wang et al. 2012). Hence, further electrochemical and amperometric measurements were carried out at the optimized potential of + 0.6 V vs. Ag/AgCl.

### Language ###
English

### Assessment ###
We can ask about the specific voltage at which glucose oxidation was observed in this electrochemical process.

### Query ###
At what voltage does glucose oxidation typically occur in electrochemical detection?

Note: This is a natural question someone might ask when studying electrochemical detection methods, and the text contains the specific answer (+0.6 V) mentioned multiple times.
At what voltage does glucose oxidation typically occur in electrochemical detection?

Note: This is a natural question someone might ask when studying electrochemical detection methods, and the text contains the specific answer (+0.6 V) mentioned multiple times.