Colorimetric Chemosensor for Hg²⁺ Based on Nuclear Fast Red and a Cationic Polyelectrolyte in Aqueous Solution

Area of Science:

• Analytical Chemistry
• Materials Science
• Environmental Science

Background:

• Mercury ions (Hg2+) pose significant environmental and health risks.
• Developing sensitive and selective detection methods for Hg2+ is crucial.
• Colorimetric chemosensors offer a simple and cost-effective detection approach.

Purpose of the Study:

• To develop a novel colorimetric chemosensor for Hg2+ detection.
• To utilize readily available materials: nuclear fast red (NFR) and poly(diallyldimethylammonium chloride) (PDADMAC).
• To achieve detection under physiological conditions in aqueous solutions.

Main Methods:

• Fabrication of a chemosensor by mixing an anionic dye (NFR) with a cationic polyelectrolyte (PDADMAC).
• Spectrophotometric analysis to observe changes in absorption spectra upon Hg2+ addition.
• Visual observation of color changes for qualitative detection.

Main Results:

• The developed chemosensor exhibited a bathochromic shift upon Hg2+ addition.
• A distinct color change from pink to reddish violet was observed, detectable by the naked eye.
• NFR alone did not show this color change, highlighting PDADMAC's role in Hg2+ detection.

Conclusions:

• A simple and effective colorimetric chemosensor for Hg2+ detection was successfully developed.
• The combination of NFR and PDADMAC provides a valuable platform for sensing applications.
• This method offers a straightforward approach for visual Hg2+ detection in aqueous environments.