Polymer-based recyclable solid-phase optical sensor to quantify Hg²⁺ in aqueous samples.

Area of Science:

• Materials Science
• Analytical Chemistry
• Environmental Science

Background:

• Mercury (Hg2+) is a toxic heavy metal pollutant with significant environmental and health impacts.
• Accurate and sensitive detection methods are crucial for monitoring mercury contamination.
• Existing methods may lack portability, selectivity, or sensitivity for real-time analysis.

Purpose of the Study:

• To engineer a facile and portable solid-state sensor for selective colorimetric detection of Hg2+.
• To develop a sensor with high sensitivity and selectivity for trace-level mercury detection.
• To validate the sensor's performance in complex environmental matrices.

Main Methods:

• Fabrication of a hierarchically organized macro/mesoporous polymeric monolith.
• Integration of a synthetically tailored chromoionophoric probe (DPQD) into the poly(acrylic acid-co-trimethylolpropane triacrylate) [poly(AA-co-TMPTA)] matrix.
• Characterization using SEM, TEM, UV-Vis, FTIR, and XRD.
• Colorimetric detection of Hg2+ based on charge-transfer complex formation.

Main Results:

• The poly(AA-co-TMPTA)DPQD sensor exhibited a distinct color change from yellow to orange upon Hg2+ interaction.
• Achieved a low detection limit of 0.23 ppb for Hg2+ with a linear response range of 0.02-100 ppb.
• Demonstrated high selectivity for Hg2+ over other metal ions and maintained >90% efficacy after 7 reuse cycles.
• Validated successfully in environmental water, industrial wastewater, and tobacco extract samples with high recovery rates.

Conclusions:

• The developed solid-state sensor offers a portable and selective method for Hg2+ detection.
• The hierarchical porous structure enhances analyte capture and probe immobilization.
• The sensor shows practical applicability for real-time, in situ monitoring of mercury contamination in diverse environments.