Selective fluorescent Hg(II) detection in aqueous solutions with a dye intermediate

Area of Science:

• Analytical Chemistry
• Environmental Science
• Materials Science

Background:

• Mercury(II) is a toxic heavy metal pollutant requiring sensitive detection methods.
• Fluorescent chemosensors offer a promising approach for real-time, selective ion detection.
• 1-amino-8-naphthol-3,6-disulfonic acid sodium (ANDS) is a dye intermediate with potential sensing capabilities.

Purpose of the Study:

• To develop and characterize a novel fluorescent chemosensor for selective Hg(II) detection.
• To investigate the sensing mechanism based on fluorescence quenching.
• To evaluate the analytical performance and applicability in real water samples.

Main Methods:

• Utilized 1-amino-8-naphthol-3,6-disulfonic acid sodium (ANDS) as a fluorescent probe.
• Investigated the fluorescence quenching mechanism upon interaction with Hg(II) in aqueous solution.
• Determined the complex stoichiometry and binding constant.
• Evaluated sensor performance including linear range, limit of detection, pH range, and selectivity.
• Applied the developed sensor for Hg(2+) detection in environmental water samples.

Main Results:

• ANDS exhibited strong fluorescence quenching in the presence of Hg(II), indicating selective recognition.
• A 2:1 complex formation between Hg(II) and ANDS was identified with a binding constant (K) of 6.2 x 10^9.
• The developed fluorescent chemosensor demonstrated a linear response for Hg(II) from 2.9 x 10^-6 to 5.5 x 10^-5 M.
• A low limit of detection (LOD) of 5.3 x 10^-7 M was achieved within a working pH range of 5.0–9.0.
• The sensor showed excellent selectivity for Hg(II) over various other metal ions.
• Successful application of the method for detecting Hg(2+) in real water samples was demonstrated.

Conclusions:

• A highly selective and sensitive fluorescent chemosensor for Hg(II) detection was successfully developed using ANDS.
• The fluorescence quenching mechanism provides a reliable basis for quantitative Hg(II) determination.
• The developed sensor is a viable tool for environmental monitoring of mercury contamination in water samples.