Quantitative SERS sensor based on self-assembled Au@Ag heterogeneous nanocuboids monolayer with high enhancement...

Area of Science:

• Nanotechnology
• Analytical Chemistry
• Spectroscopy

Background:

• Accurate detection of pesticides and pollutants is crucial for food, environmental, and human health security.
• Surface-enhanced Raman spectroscopy (SERS) requires substrates with high Raman enhancement and repeatability for reliable quantitative analysis.

Purpose of the Study:

• To develop a quantitative SERS sensor for detecting trace pesticides and pollutants.
• To utilize self-assembled plasmonic Au@Ag heterogeneous nanocuboids (Au@Ag NCs) monolayer for enhanced SERS performance.

Main Methods:

• Fabrication of large-scale monolayer films of densely packed Au@Ag NCs.
• Chemical functionalization using 4-methyl-thiobenzoic acid (4-MBA) to create numerous 'hot spots' within nanogaps.
• Utilizing crystal violet (CV) as a probe molecule to assess SERS performance and uniformity.

Main Results:

• The Au@Ag NCs monolayer demonstrated high SERS performance and uniformity.
• The sensor successfully quantified trace thiabendazole (TBZ) in pears at 0.0105 nM and malachite green (MG) in fishpond water at 0.87 nM.
• The developed sensor exhibits excellent sensitivity and repeatability for quantitative detection.

Conclusions:

• The proposed SERS sensor based on Au@Ag NCs is effective for quantitative analysis of contaminants.
• This strategy is suitable for on-site analysis and supervision of contaminants in food and environmental samples.
• The sensor offers a promising tool for ensuring food and environmental security.