The imminent release of engineered nanomaterials (ENMs) into the environment has necessitated the development of sophisticated analytical metrology to detect and characterize these emerging contaminants in complex samples. The detection of engineered nanomaterials in environmental samples is impeded by their expected low release concentrations (ng L-1), small size (1-100nm), and the ubiquitous presence of naturally occurring nanomaterials. Single-particle ICP-MS has emerged as a sensitive and robust technique for the detection and characterization of ENMs at environmentally relevant concentrations, providing both particle number concentration and size information for a given sample. Moreover, recent advances in the development of this technique have overcome analytical obstacles such as high particle number concentration (resulting in “coincidence”) and high dissolved background. The implementation of microsecond dwell times result in the temporal acquisition of a nanoparticulate signal, increasing the particle resolution and simultaneously reducing or eliminating signal generated from background ionic or molecular interferences. These advances enhance the analytical working range of this technique, and expand its applicability to a wider range of complex matrices. The challenge of detecting ENMs amidst a high concentration of naturally occurring analogues persists and requires a more methodical approach. Three different approaches utilizing ICP-MS are discussed as bulk elemental ratios, size fractionation (e.g. field-flow fractionation) coupled to ICP-MS, and particle-by-particle analysis using microsecond spICP-MS are proposed as possible solutions to differentiating between naturally occurring and engineered nanomaterials. The detection and characterization of these materials in the environment is a crucial step towards developing accurate life cycle assessments, and will require further development of these techniques.
"Advances in the detection and characterization of engineered nano particles in the environment using microsecond single particle icp-ms", Dr. Manuel D. Montaño, Dept. of Chemistry, Colorado School of Mines
Thursday, October 30, 2014 - 3:00pm
207 Hudson Hall