Renewal Mechanism of UV-Ozone-Cleaning Process on Contaminated Screen-Printed Carbon Electrodes

Abstract

Screen-printed carbon electrode (SPCE) has been extensively applied in electrochemical (EC) detection due to its excellent characteristics and low cost. However, SPCE is more likely to be contaminated that seriously affects the sensitivity and reproducibility of detection. In this paper, UV-ozone-cleaning process was utilized to solve this problem. Renewal mechanism of UV-ozone-cleaning on contaminated SPCE was firstly investigated in detail, in which the level of SPCE contamination was represented by interfacial impedance. Both scanning electron microscopy and X-ray photoelectron spectroscopy were employed to evaluate the surface morphology and chemical constituents of SPCE respectively. The results indicate that the significant EC enhancement was mainly attributed to the removal of contaminants, the increase of both reaction area and surface oxygen functional groups. To further demonstrate the renewal effect, the determination of nicotinamide adenine dinucleotide was performed. Compared with the contaminated SPCE, the UV-ozone-cleaned SPCE exhibits better EC response that the anodic peak current increased by 6∼28% and the sensitivity increased from 13.31 to 19.11 μA·mM−1. Moreover, the cleaned SPCE shows good reproducibility with the low standard deviation of peak current and oxidation potential.