Abstract
Two-dimensional materials may constitute key elements in the development of a sensing platform where extremely high sensitivity is required, since even minimal chemical interaction can generate appreciable changes in the electronic state of the material. In this work, we investigate the sensing performance of epitaxial graphene on Si-face 4H-SiC (EG/SiC) for liquid-phase detection of heavy metals (e.g., Pb). The integration of preparatory steps needed for sample conditioning is included in the sensing platform, exploiting fast prototyping using a 3D printer, which allows direct fabrication of a microfluidic chip incorporating all the features required to connect and execute the Lab-on-chip (LOC) functions. It is demonstrated that interaction of Pb2+ ions in water-based solutions with the EG enhances its conductivity exhibiting a Langmuir correlation between signal and Pb2+ concentration. Several concentrations of Pb2+ solutions ranging from 125 nM to 500 µM were analyzed showing good stability and reproducibility over time.
Highlights
Nowadays, among water pollutants, heavy metals (HMs) are considered as the most serious source to pollute the biosphere, posing a significant threat to human health, because they are nonbiodegradable and can be accumulated in soft tissues [1]
We developed and tested a reusable lab-on-chip for heavy metals detection, in which the 3D printed microfluidic cell allowed the interaction between the HMs solutions and the sensing surface
The resistance value reported (ΔR) is the net resistance measured as the difference between the signal due to the presence of Pb2+ and the recovery value obtained by cleaning of the chip after each measurement cycle
Summary
Among water pollutants, heavy metals (HMs) are considered as the most serious source to pollute the biosphere, posing a significant threat to human health, because they are nonbiodegradable and can be accumulated in soft tissues [1]. Some HMs are essential minerals for healthy biochemical and physiological function, since they serve as components of several key enzymes and play important roles in various oxidation-reduction reactions in human bodies. Others, such as lead, chromium, arsenic, and mercury are toxic even when ingested in very small quantities [2]. Very small changes in e.g., conductivity can be detected leading to high-resolution sensors. Driven by these features, we investigated the Proceedings 2018, 2, 982; doi:10.3390/proceedings2130982 www.mdpi.com/journal/proceedings
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