Colorimetric Differentiation of Multiple Oxidizing Anions Based on Two Core-Shell Au@Ag Nanoparticles with Different...

Area of Science:

• Environmental Chemistry
• Nanotechnology
• Analytical Chemistry

Background:

• Efficient discrimination of oxidizing anions is crucial for environmental monitoring.
• Existing methods for detecting oxidizing anions can be complex and time-consuming.
• Development of rapid and sensitive detection methods is needed.

Purpose of the Study:

• To develop a simple, fast, and efficient colorimetric sensor array for the detection and identification of oxidizing anions.
• To utilize the differential etching of silver shells on core-shell gold-silver nanoparticles (Au@Ag NPs and Au@Ag NCs) for anion sensing.
• To achieve sensitive detection and discrimination of multiple oxidizing anions and their mixtures.

Main Methods:

• Fabrication of core-shell gold-silver nanoparticles (Au@Ag nanospheres and Au@Ag nanocubes).
• Utilizing the differential etching of the silver shell by various oxidizing anions to induce distinct colorimetric responses.
• Employing the Au@Ag nanoparticles as receptors and indicators in a sensor array format.
• Analyzing absorbance and color changes to identify specific oxidizing anions.

Main Results:

• The sensor array successfully identified six oxidizing anions (BrO3-, Cr2O72-, ClO4-, IO3-, IO4-, and MnO4-) down to 10 nM concentrations.
• Differential etching of the silver shell by anions led to unique absorbance and color changes, enabling discrimination.
• The array demonstrated effective discrimination of complex mixtures of oxidizing anions.
• Successful application of the sensor array for detecting oxidizing anions in real environmental samples (river water and tap water).

Conclusions:

• A novel and efficient colorimetric sensor array based on Au@Ag nanoparticles has been developed for oxidizing anion detection.
• The sensor array offers a simple, fast, and sensitive method for identifying multiple oxidizing anions and their mixtures.
• The developed sensor array shows practical applicability for environmental monitoring of oxidizing anions in water samples.