Near Real-Time Measurement of Airborne Carbon Nanotubes with Metals Using Raman-Spark Emission Spectroscopy

Area of Science:

• Environmental Science
• Analytical Chemistry
• Materials Science

Background:

• Carbon nanotubes (CNTs) are increasingly used, necessitating methods to monitor airborne exposure.
• Accurate quantification of single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) in the air is crucial for risk assessment.
• Detecting toxic metals within CNTs is vital for understanding their potential health impacts.

Purpose of the Study:

• To develop a near real-time method for analyzing airborne SWCNTs and MWCNTs.
• To simultaneously detect toxic metals present within airborne CNTs.
• To establish a sensitive and accurate monitoring technique for nanomaterial exposure.

Main Methods:

• Combined Raman spectroscopy and spark emission spectroscopy for molecular and elemental analysis.
• Utilized a corona-based aerosol microconcentrator for enhanced airborne CNT sampling.
• Established linear relationships between signal intensity and analyte mass for quantitative analysis.

Main Results:

• Achieved low limits of detection (LOD) for airborne CNTs: 0.09 μg/m³ (SWCNT) and 0.81 μg/m³ (MWCNT) with a 10-minute sampling time.
• Demonstrated excellent performance for metal detection with mass LODs of 0.8-0.9 ng for Co and Ni, and 35.09 ng for Fe.
• Confirmed linear relationships (high R² values) between spectral signals and analyte mass.

Conclusions:

• The developed method provides near real-time monitoring of airborne CNTs and associated toxic metals.
• Offers advantages of low LOD, high accuracy, and portability for nanomaterial analysis.
• Represents a valuable tool for occupational health, environmental monitoring, and safety applications.