Multiple toxic heavy metal ions detection based on graphene quantum dots optical sensing

• Main Author: Loh, Jun Jie
• Other Authors: Chen Peng
• Format: Final Year Project
• Language: English
• Published: 2017
• Subjects: DRNTU::Engineering::Bioengineering
• Online Access: http://hdl.handle.net/10356/72180
• Institution: Nanyang Technological University

Heavy metals including chromium, lead and mercury have huge negative impacts on human health and the environment. Chromium, lead and mercury can induce numerous organ damage such as autoimmune diseases, kidney and nervous system damage. It is thus essential to be able to detect such metal ions, including in the environment and water bodies. There are numerous traditional detection techniques, such as electrochemical ion selective electrodes, Auger-electron spectroscopy, polarography, atomic absorption and emission spectroscopy and inductively coupled plasma-mass spectrometry. However, these methods requires a long process period, sophisticated instruments, complex sample preparation and are bulky and costly. Graphene quantum dots are considered superior for various functionalities including fluorescent probes for sensing and bioimaging due to their excellent characteristics such as high tunable photoluminescence, molecular size, chemical inertness, good water solubility, convenient functionalization and modification, high photostability, high biocompatibility and low toxicity. This project involves designing optical sensors based on the fluorescence quenching of pyrene-GQDs and carbon black-GQDs to detect Cr3+, Pb2+ and Hg2+ to assess the GQDs selectivity as optical sensors for the detection of these metals. From the experimental results, the different functionalized GQDs can be used for detection of different targets. For example, carbon black-GQDs is optimal for fluorescence detection of Cr3+ and pyrene-GQDs is optimal for fluorescence detection of Pb2+ and Hg2+.