This research will develop methods for the detection and monitoring of engineered nanomaterials in aquatic systems. Advanced low-invasive fractionation techniques will be refined to fractionate across the nanoscale (e.g. between 2 and 450 nm). Elemental distributions, size and charge distributions, as well as isotopic signatures and morphology, will be explored among various sources of engineered and other nanomaterials. Critical steps in the research include developing a new analytical methodology (SPLITT) that splits elements into dissolved versus particulate fractions. Research will explore to what extent SPLITT fractionates nanomaterials that have equilibrated with aquatic media. It will also examine the optimal fields for different nanomaterial sources, and to what extent composition, size, and charge distributions affects differentiation: (a) between natural and incidental/engineered nanomaterials and (b) among various sources of a nanoparticle class. The research will determine to what extent existing manufacturing processes produce nanomaterials with distinct isotopic signatures relative to natural and incidental nanomaterials and among various sources of a nanoparticle class. Broader impacts of this work include significant outreach to students and teachers at the K-12 level. It also supports an investigator at an institution in an EPSCOR state.
Outcome or Accomplishment: While many analytical strategies exist for determining particle characteristics such as size, all exhibit weaknesses that limit their applicability to distributed mixtures of nanoparticles. Methods that capitalize on both surface charge and size of particles would provide broad capability for separating nanoparticles, yet these methods have been limited to date by the high diffusion rates of nanoparticles. We have resolved the diffusion challenges associated with nanoparticle separation using biased cyclical electric fields to yield a new method called biased cyclical electrical field flow fractionation (BCyElFFF). Impact or Benefits: Separation of nanoparticles from mixtures is an analytical capability of critical importance to nanotechnology and its environmental implications. Characterization and monitoring will be enhanced in many contexts including characterization of engineered nanomaterials in the laboratory, in biological systems, and the environment. Two patent applications have resulted from this work. Explanation/Background: The investigators, who are from science and engineering colleges at the University of Utah, collaborate with researchers at other universities in Utah, Thailand, and France to develop new approaches to improve nanoparticle detection and characterization in aquatic systems. Primary Strategic Outcome Goal: (1) Research Infrastructure for detection and characterization of nanomaterials in aquatic systems Secondary Strategic Outcome Goal(s): (2) Discovery of new understanding of the natural distribution of elements among the nano- to micro-particulate size fractions in natural systems, and the behavior of engineered nanomaterials in these systems. Transformative Research: Development of methods/instrumentation to separate nanoparticles from mixtures via combined charge and size characteristics will lead to more effective characterization and monitoring and novel understanding of their transport and fate in biological and environmental systems. Intellectual Merit: New methods/instrumentation to separate nanoparticles from mixtures via combined charge and size characteristics. New understanding of nanoparticle transport and fate in biological and environmental systems.
