Increasing use of engineered nanoparticles (NPs) in consumer products has led to concern that these materials will enter the environment. Once released, a variety of transformations such as dissolution and aggregation may alter the original material. Single particle � inductively coupled plasma � mass spectrometry (SP-ICP-MS) was used to determine size distributions over time for various sizes and shapes of NPs in varied environmentally relevant media. Silver nanowires were spiked into a simulated freshwater and a D. magna test media to monitor their size distributions. Samples were analyzed by SP-ICP-MS to observe transformations over toxicity test time periods. A decrease in the number of particles observed over time in both media suggests dissolution of nanowires. Tap water and wastewater were spiked with spherical Ag NPs, Ag+, or a combination of the two at environmentally relevant concentrations. We determined under what conditions NPs may dissolve, aggregate, or form complexes, and if particles interact with free Ag+ in solution. Water chemistry components, specifically chloride and sulfide, were investigated as to how they may transform Ag NPs or interact with dissolved Ag+. Using SP-ICP-MS, changes in NP size, through aggregation and complexation, were determined.  Bioaccumulation tests were performed using the worm Eisenia fetida and both Au and Ag NPs.  Worm tissue was extracted using a 25% tetrametylammonium hydroxide (TMAH) solution, allowing tissue to dissolve while leaving NPs intact.  Differences in uptake of both Au and Ag NPs (size range 50 to 100 nm) were investigated with respect to particle size.

Use of single particle – inductively coupled plasma – mass spectrometry for analysis of engineered nanoparticle stability in varied media

244th National Meeting (2012)

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