Immobilised cytochrome c on the carbon dots functionalised MWCNTs and its application to hydrogen peroxide detection

We have prepared the carbon dots (C-dots) by sucrose carbonisation in the presence of sulphuric acid and characterised by transmission electron microscopy, Fourier transform infrared spectra, fluorescence spectroscopy and UV–vis absorption spectra. The resultant C-dots could be used for the activation of CNTs. Cytochrome c immobilised on the functionalised multi-walled carbon nanotube-modified glass carbon electrode was found to promote electron transfer that was investigated by electrochemical methods. The obtained electrode can also be used as a biocatalyser to catalyse the reduction of H₂O₂. Under optimal conditions, the constructed H₂O₂ sensor showed two linear segments and the detection limits were 1.02 and 2.59 µM (S/N = 3). The modified electrode displayed high stability, good reproducibility and excellent selectivity.