A Localized Surface Plasmon Resonance (LSPR)-based, simple, receptor-free and regeneratable Hg(2+) detection system

Area of Science:

• Nanomaterials Science
• Analytical Chemistry
• Environmental Sensing

Background:

• Mercury ions (Hg2+) are toxic environmental pollutants.
• Accurate and sensitive detection of Hg2+ is crucial for environmental monitoring.
• Existing sensors often require complex receptor molecules or lack regenerability.

Purpose of the Study:

• To develop a simple, receptor-free, and regeneratable sensor for Hg2+ detection.
• To utilize localized surface plasmon resonance (LSPR) shifts for quantitative Hg2+ sensing.
• To demonstrate the sensor's performance in real-world water samples.

Main Methods:

• Gold nanorods (GNRs) immobilized on a glass slide were used as the sensing platform.
• Hg2+ coordination with citrate induced precipitation, altering the local refractive index (RI) near the GNRs.
• Changes in LSPR absorption peak (red-shift) were correlated with Hg2+ concentration.

Main Results:

• The sensor detected Hg2+ quantitatively over a concentration range of 1 nM to 1 mM.
• A low limit of detection (LOD) of 0.38 nM was achieved with good linearity (R²=0.9507).
• High selectivity for Hg2+ was observed, with minimal response to other metal ions, and the sensor was reusable for at least eight cycles.

Conclusions:

• A novel sensing strategy combining Hg2+-citrate precipitation and LSPR red-shift was successfully developed.
• The developed sensor is simple, regeneratable, selective, and sensitive for Hg2+ detection.
• The sensor shows promise for practical application in monitoring mercury contamination in water sources.