A chalcogenide-based colorimetric sensor on paper for heavy metal ions detection

• Main Author: Chua, Huoy Jing
• Other Authors: Lee Hiang Kwee
• Format: Thesis-Master by Research
• Language: English
• Published: Nanyang Technological University 2022
• Subjects: Science::Chemistry
• Online Access: https://hdl.handle.net/10356/163946
• Institution: Nanyang Technological University

With the ongoing Flint and Newark water crises, heavy metal ions (HMIs) detection is imperative to safeguard against its detrimental effects. Some conventional methods to detect HMIs include optical emission spectroscopy (OES) and atomic absorption spectroscopy (AAS). However, these techniques are considered to be time-consuming, labour-intensive, costly, and require specialized technical personnel to operate complex instrumentation. Moreover, it is not amenable to on-site HMIs analysis in remote locations due to the centralized nature of these methods. As such, colorimetric sensors have gained traction due to its ease of operation, cost-effectiveness, and are readily deployable as its operation can be decentralized. Herein, we employ ZnS sensor-on-paper for colorimetric detection of HMIs and harness the synergistic concepts of superhydrophobicity and chalcogenide activation to enhance the sensor’s analytical response. Characterization of the sensor before and after exposure to HMIs, selectivity studies and practical applications of our sensor-on-paper device would also be discussed. The LOD achieved by the sensor was determined to be 1 μM (for Pb2+, Cu2+, and Hg2+) and 10 μM (for Ag+).