Size-Resolved SERS Detection of Trace Polystyrene Nanoplastics via Selective Electrosorption

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Microplastics and nanoplastics are pervasive environmental contaminants.
• Accurate detection and characterization of nanoplastics, especially by size, remain challenging.
• Existing spectroscopic methods struggle with selective size-based nanoplastic analysis.

Purpose of the Study:

• To develop a simple, rapid, and size-resolved analytical method for trace polystyrene (PS) nanoplastics.
• To utilize electrosorption combined with surface-enhanced Raman spectroscopy (ES-SERS) for nanoplastic analysis.
• To achieve selective detection of nanoplastics across a size range of 20 to 300 nm.

Main Methods:

• A hyphenated electrosorption and surface-enhanced Raman spectroscopy (ES-SERS) technique was developed.
• Rough silver was employed as both the electrode for electrosorption and the substrate for SERS.
• Positive electric potential was applied to adsorb PS nanoplastics onto silver nanostructures.

Main Results:

• The ES-SERS method achieved sensitive detection limits for PS nanoplastics (e.g., 30 ng/L for 20 nm).
• Smaller nanoplastics exhibited higher analytical enhancement factors.
• Selective enrichment and detection of specific nanoplastic sizes were achieved by controlling electrosorption time.

Conclusions:

• The developed ES-SERS method provides a powerful tool for size-resolved nanoplastic analysis.
• This technique successfully detected nanoplastics released from disposable beverage cup lids.
• ES-SERS opens new avenues for monitoring nanoplastic pollution with enhanced specificity.