KEYNOTE Application of geochemical tools in nanotechnology health and safety

Analytical and sampling techniques capable of detecting engineered nanomaterials are needed, due to concern about their potential release into the environment, and concern about worker exposures during manufacturing and... [ view full abstract ]

Analytical and sampling techniques capable of detecting engineered nanomaterials are needed, due to concern about their potential release into the environment, and concern about worker exposures during manufacturing and handling processes. This presentation describes the use of catalysts and other metal impurities in carbon nanotubes (CNT) as tracers for monitoring CNT releases. Selection of an appropriate CNT tracer requires knowledge of the metal impurities in the CNT material being handled, and knowledge of potential interferences from background sources. The most common catalyst elements are transition metals, such as Fe, Ni, Mo, Y, Co, Cu, and Cr, but other elements may occur as trace impurities in CNTs. The impurities that are most likely to be useful tracers are those that exist as trace elements in the environment (low mg/kg range), but are elevated in the CNTs (1000 mg/kg and higher). ICP-MS has the sensitivity required to determine metal impurities in CNTs, and is also suitable for analysis of sample substrates (e.g., air filters, surface wipes) commonly used for workplace monitoring. Useful geochemical approaches include spatial concentration mapping and interpretation of elemental and/or isotopic signatures. These well-established geochemical tools can assist in identifying CNT releases in indoor and outdoor environments, monitoring the effectiveness of control measures, and distinguishing released CNTs from background particles.