Rhodamine-Functionalized Nanosensor for Multimodal, Ultrasensitive, and Stable Detection of Toxic Mercury Ions

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Heavy metal pollutants, particularly mercury (II), pose significant risks to public health and food safety.
• Existing detection methods often lack the sensitivity required for nanomolar-level detection in aqueous environments.

Purpose of the Study:

• To develop a novel, highly sensitive nanoprobe for the detection of mercury (II) ions.
• To create a cost-effective and practical nanosensor for real-world environmental and food safety applications.

Main Methods:

• Fabrication of a self-assembled amphiphilic dual rhodamine B nanoprobe (DR) forming stable nanospheres.
• Evaluation of the nanosensor's selectivity, response time, and detection limit in aqueous solutions.
• Validation of the nanoprobe's performance using smartphone-based analysis, hydrogel sensors, and paper-based test strips.

Main Results:

• The DR nanoprobe achieved an ultralow detection limit of 0.19 nM for Hg²⁺ with a rapid 12-s "turn-on" fluorescence response and visible colorimetric changes.
• The nanosensor demonstrated high selectivity and robustness across diverse real-world samples, including agricultural products, soil, water, and biological specimens.
• Recovery rates ranged from 97.0% to 107.5%, confirming the practical utility of the developed system.

Conclusions:

• The developed DR nanoprobe offers a superior solution for ultrasensitive Hg²⁺ detection compared to existing systems.
• The integration of cost-effective synthesis with multi-modal detection platforms provides a promising tool for environmental monitoring and food safety assurance.