A highly sensitive and selective fluorescent chemodosimeter for Hg2+ in neutral aqueous solution

Area of Science:

• Analytical Chemistry
• Environmental Science
• Materials Science

Background:

• Mercury ions (Hg2+) pose significant environmental and health risks due to their toxicity.
• Sensitive and selective detection methods for Hg2+ are crucial for environmental monitoring and safety assessments.
• Existing detection methods may lack sensitivity, selectivity, or require complex sample preparation.

Purpose of the Study:

• To develop a novel fluorescent chemodosimeter for the sensitive and selective detection of Hg2+.
• To investigate the reaction mechanism underlying the fluorescence response to Hg2+.
• To establish the analytical performance of the developed assay for Hg2+ quantification.

Main Methods:

• Synthesis and characterization of N-[p-(dimethylamino)benzamido]-N'-phenylthiourea (1) as a fluorescent probe.
• Evaluation of the probe's fluorogenic chemodosimetric behavior towards various metal ions.
• Spectroscopic analysis (ESI mass, IR) to elucidate the reaction mechanism.
• Fluorescence titration to determine the linear detection range and limit of detection.

Main Results:

• The probe exhibited high sensitivity and selectivity for Hg2+ in neutral aqueous solutions.
• A strongly fluorescent 1,3,4-oxadiazole derivative was formed via a Hg2+-promoted desulfurization reaction.
• A good linear relationship was observed between fluorescence intensity and Hg2+ concentration from 1.0 x 10(-7) to 2.0 x 10(-5) mol L(-1).
• The limit of detection for Hg2+ was determined to be as low as 3.1 x 10(-8) mol L(-1).

Conclusions:

• A novel fluorescent assay for Hg2+ detection has been successfully developed.
• The assay demonstrates excellent sensitivity and selectivity, making it suitable for practical applications.
• The underlying Hg2+-promoted desulfurization reaction provides a reliable mechanism for fluorescence generation.