Sub-10 nm Nanoparticle Detection Using Multi-Technique-Based Micro-Raman Spectroscopy

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Microplastic and engineered nanoparticle pollution poses risks to organisms and ecosystems.
• The abundance of nano-sized pollutants is increasing, yet their risks remain largely unknown due to limited characterization techniques.
• Current methods for nanoparticle characterization are often complex and time-consuming.

Purpose of the Study:

• To develop a reliable, multi-technique approach for characterizing nanoparticles down to 10 nm.
• To demonstrate the capability of standard micro-Raman spectroscopy and atomic force microscopy for single nanoparticle analysis.
• To provide a more accessible alternative to advanced techniques like Tip-Enhanced Raman Spectroscopy.

Main Methods:

• Utilizing a combination of standard micro-Raman spectroscopy and standard atomic force microscopy.
• Achieving single-particle spectral analysis for nanoparticles.
• Characterizing polystyrene (25 nm) and titanium dioxide (9 nm) nanoparticles.

Main Results:

• Successfully obtained single-particle spectra from 25 nm polystyrene and 9 nm TiO2 nanoparticles.
• Achieved mass limits of detection as low as 1.6 attograms for TiO2 nanoparticles.
• Demonstrated unambiguous Raman signal detection from single, small nanoparticles.

Conclusions:

• The proposed multi-technique approach enables sensitive characterization of nano-sized pollutants.
• This method offers a viable and efficient alternative to more complex nanoparticle analysis technologies.
• The findings pave the way for better understanding and mitigation of nano-pollutant risks.