A novel electrochemical sensor based on sodium alginate-decorated single-walled carbon nanotubes for the direct electrocatalysis of heavy metals ions

Abstract

In recent years, the presence of heavy metal ions in food chains and water poses serious environmental and human health problems. Therefore, there has been a pressing need for fast simple, sensitive, and accurate methods for their detection. In this study a novel electrochemical sensor based on alginate sodium biopolymer decorating single-walled carbon nanotubes was elaborated for the detection of trace level of heavy metal ions. Different brown algae were used to extract sodium alginate, with Cystoseira being the most common. Due to its high extraction yield and high mannuronate/guluronate (M/G) ratio, Compress a brown algae was chosen to disperse with single-walled carbon nanotubes. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy were monitored to investigate each surface modification. Differential pulse anodic stripping voltammetry (DPASV) was used to follow the electrochemical heavy metal ions determination. Moreover, the performance of the optimized heavy metal ions sensor in terms of sensitivity, linear range, limit of detection, and reproducibility was investigated. The detection limits were found to be 0.1, 31, and 1 nM for Pb2+, Cd2+, and Cu2+, respectively. The results reported in this work showed good stability, high sensitivity, and appealing inter-electrode repeatability. Finally, lead detection in tap water was carried out. The metrological performance of the present sensor makes it a good alternative for heavy metal ions detection.