Fig. 5

Amperometric responses of CuO/C-400 °C upon the consecutive addition of glucose in a artificial serum and c artificial saliva at 0.5 V (vs. Ag/AgCl); the corresponding calibration curves of the CuO/C-400 °C for the glucose detection in b artificial serum and d artificial saliva; e Amperometric i-t response of the CuO/C-400 °C electrodes at 0.5 V (vs. SCE) for different samples; f The relative current strength of the electrode within 28 days