Metal fingerprinting and chemothermal isolation methods to quantify natural and engineered carbon nanoparticles

Desiree Plata (PI) and P. Lee Ferguson (co-PI)
Funding Agency: 
NSF Environmental Engineering

Our aim in this project is to develop methodology to quantify, fingerprint, and distinguish natural and engineered carbonaceous nanoparticles using thermal separation techniques and metal content signatures. Building on well-established thermal methods to quantify black carbon (BC) soot, we will utilize a combination of techniques that distinguish non-nanoparticulate natural organic matter, single-walled carbon nanotubes (SWCNTs), and BC (the most ubiquitous, natural carbonaceous nanoparticle) based on their distinct thermal stabilities. Preliminary results suggest that natural organic matter, SWCNTs, and BC have unique oxidation ranges and could be distinguished and quantified following sequential oxidations coupled with elemental analysis. Here, we aim to demonstrate that these thermal stabilities are preserved in complex mixtures of air, water, sediments, and soil, and as a result, can be used to quantitatively delineate the nanoparticles (e.g., natural vs. engineering) in environmental matrices. Furthermore, bulk metal contents determined via complete acid digestion and mass spectrometry should provide a route toward source apportionment. Advantages of this approach include the low cost, accessibility, high-throughput capabilities, and minimal sample processing (e.g., extraction) required for this method, which reduces the potential for analyte loss and transformation during analysis.