Self-assembled supramolecular sensor for hydrogen sulfate via multipoint hydrogen bonding: real-sample analysis and...

Area of Science:

• Supramolecular Chemistry
• Analytical Chemistry
• Materials Science

Background:

• Development of selective and sensitive chemical sensors is crucial for environmental and health monitoring.
• Hydrogen sulfate (HSO₄⁻) detection is important in various industrial and biological processes.
• Existing methods for HSO₄⁻ detection often lack sensitivity, selectivity, or portability.

Purpose of the Study:

• To develop a self-assembled supramolecular probe for selective and sensitive detection of hydrogen sulfate (HSO₄⁻) ions.
• To investigate the photophysical properties and sensing mechanism of the probe.
• To demonstrate the practical applicability of the probe in real-world samples.

Main Methods:

• Synthesis of a rhodamine-indole based supramolecular probe (compound 1).
• Characterization of probe assembly using Dynamic Light Scattering (DLS) and Field Emission Scanning Electron Microscopy (FESEM).
• Spectroscopic analysis (fluorescence) to determine sensing response and mechanism.
• Validation using commercial shampoo samples and paper-strip sensors for smartphone-assisted detection.

Main Results:

• Compound 1 exhibited aggregation-assisted photophysical modulation, forming nanoscale assemblies.
• A distinct ratiometric fluorescence response was observed upon HSO₄⁻ interaction, with a detection limit of 0.03 µM.
• The probe showed high selectivity for HSO₄⁻ over other anions and reversible sensing behavior.
• Successful application in detecting HSO₄⁻ in shampoo samples and via portable paper-strip sensors.

Conclusions:

• A self-assembly-driven supramolecular strategy provides a robust platform for developing portable and sustainable sensors for anionic species.
• The developed probe offers a sensitive, selective, and user-friendly method for HSO₄⁻ detection.
• The smartphone-assisted detection system demonstrates the potential for on-site and real-time analysis.