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Laser Detection of Nanoparticles In the Environment
Citation:
JONES-LEPP, T. L., K. R. ROGERS, AND R. Snell. Laser Detection of Nanoparticles In the Environment. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-11/097, 2011.
Impact/Purpose:
This report covers efforts to investigate a relatively new technology, nanoparticle tracking analysis (NTA) for use in identifying nanoparticles. NTA is a laser-based instrument capable of real-time tracking of nanoparticles in solution. NTA was evaluated as a stand-alone screening method to identify and calculate particle size distributions of metal-based, engineered nanomaterials (ENMs) in situ and in laboratory synthesized environmental water samples. Based on the information considered here, overall NTA sensitivity appeared to be good for particle sizes in the 20 - 40 nm range, and larger sizes, including the ability to follow the real-time formation of aggregates. Reliable data was more difficult to obtain for particle sizes below the 20 nm size range. Benefits of the NTA technology were that the instrumentation allowed for visualization of nanoscale particles in liquids on an individual basis, provided nanoparticle size and distribution data for each sample, and was capable of measuring large numbers of individual particles in substantially less time than required by microscopy techniques, i.e., transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM). Also included in this report are comparisons of NTA with a number of other nanoparticle characterization technologies including ultraviolet-visible spectroscopy (UV-Vis), dynamic light scattering (DLS), TEM, and ultra small angle X-ray scattering (USAXS).
Description:
The United States Environmental Protection Agency (EPA) is charged by Congress to protect the nation’s natural resources. Under the mandate of national environmental laws, the EPA strives to formulate and implement actions leading to a compatible balance between human activities and the ability of natural systems to support and nurture life. To meet this mandate, the EPA’s Office of Research and Development (ORD) provides data and scientific support that can be used to solve environmental problems, build the scientific knowledge base needed to manage ecological resources wisely, understand how pollutants affect public health, and prevent or reduce environmental risks.