A review of multi-walled carbon nanotubes-based electrochemical sensors to detect heavy metals for food packaging applications

The paper presents a substantial review of the fabrication and implementation of Multi-Walled Carbon Nano- tubes (MWCNTs)-based prototypes for electrochemical sensing applications. It showcases the development of MWCNTs using microfabrication techniques, such as chemical vapour deposition, laser ablation, electric arc discharge and their subsequent utilization in ionic detection. Carbon nanotubes (CNTs) have been found to be exceptional for electrochemical sensing applications due to their high electrical conductivity, high surface area, excellent electron transfer and high transduction capacity. As the CNTs-based sensors have been capable of detecting different kinds of ions with high sensitivity, high linearity and fast recovery and response times, the presence of various metallic ions, like lead, cadmium, cyanide and mercury ions, in food materials has been detected using pure and composite prototypes. Since the presence of any of these ions in food materials, even in small concentrations, can lead to disastrous consequences, their detection and removal are of pivotal importance. Along with the classification of the type of detected metallic ions, the challenges currently faced by these electrochemical sensors have also been shown. The concluding part expresses the practical scenario of the CNTsbased electrochemical sensors in terms of their real-time applications.