Highly selective and sensitive detection of mercuric ion based on a visual fluorescence method

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Accurate detection of trace aqueous mercuric ions (Hg2+) is crucial for environmental monitoring.
• Existing methods for mercury detection can be complex and time-consuming.
• Developing rapid, on-site detection tools for mercury pollution is a significant challenge.

Purpose of the Study:

• To develop a novel analytical method for the visual detection of aqueous Hg(2+).
• To create a portable, paper-based sensor for sensitive and selective mercury detection.
• To demonstrate the utility of functionalized quantum dots for environmental monitoring.

Main Methods:

• Synthesis of water-soluble Cadmium Selenide-Zinc Sulfide (CdSe-ZnS) quantum dots (QDs) functionalized with 2-hydroxyethyldithiocarbamate (HDTC).
• Utilizing the fluorescence quenching and color change of HDTC-modified QDs (HDTC-QDs) upon interaction with Hg(2+).
• Immobilizing HDTC-QDs onto cellulose acetate paper to create a paper-based sensor for visual Hg(2+) detection.

Main Results:

• HDTC-QDs exhibited selective and efficient fluorescence quenching by Hg(2+) via a surface chelating reaction.
• A distinct fluorescence color evolution from orange to red was observed with increasing Hg(2+) concentration.
• The paper-based sensor demonstrated a detection limit as low as 0.2 ppm for visual Hg(2+) detection.

Conclusions:

• The developed method provides a simple, effective strategy for portable and reliable fluorescence chemosensors.
• This approach facilitates on-site and instant detection of aqueous mercuric ions.
• The paper-based sensor shows significant potential for mercury pollution control and environmental monitoring.