Electrochemical characterization of tetrahedral amorphous carbon and detonation nanodiamond hybrid electrode for detection of dopamine

Abstract

This work concentrated on electrochemical characterization, that was done to evaluate tetrahedral amorphous and detonation nanodiamond (ta-C+ND) hybrid electrodes suitability for dopamine (DA) detection. Characteristics investigated in this work were (i) electrode kinetics by using ruthenium, (ii) water window in perchloric acid, (iii) sensitivity towards DA and (iv) selectivity between DA and ascorbic acid (AA).

Electrochemical characterization was carried out for ta-C and ta-C+ND electrodes with cyclic voltammetry (CV). After the characterization, ta-C+ND electrode was annealed in vacuum at 600C for 1 hour and measured again in DA solutions. Aim was to investigate how annealing affects the electrochemical performance of the hybrid electrode.

ta-C+ND hybrid electrode properties were equally good or better compared to plain ta-C, where sensitivity towards DA was enhanced. ta-C+ND had reversible kinetics, wide water window of 3.01 V and detection limit of 100 nM DA. Selectivity towards DA in presence of AA was not achieved. With annealed ta-C+ND sensitivity and kinetics towards DA improved considerably compared to non annealed ta-C+ND. In addition, annealing increased resistance to passivation of the hybrid electrode. However, properties of the hybrid electrodes changed over time and measurement results were not reproducible in DA and DA+AA solutions.

Literary review also pointed out that electrochemical behaviour of nanodiamonds is not well understood as the characterization of the used nanodiamonds is insufficient. Additionally, electrochemical experiments conducted with nanodiamonds had some inconsistencies. For more profound understanding of the phenomena, extensive characterization of surface chemistry and morphology is needed.