Engineered nanoparticles (NPs) are increasingly being used in consumer products due to their novel properties. Consequently, concerns have been raised over the potential hazards that these materials may present as a result of their release into the natural environment. This has prompted numerous investigations into the environmental behavior, transport and fate of engineered NPs. Importantly the predicted environmental concentrations of these materials is often x10 to x100 lower than the natural background levels of the element. Many studies overcome this problem with the use of high dosing concentrations, however this raises concerns regarding environmental relevance.
The work presented in this thesis demonstrates how stable isotope tracing enables the accurate detection and quantification of engineered NPs in complex biological samples even when exposures are performed at low and environmentally relevant concentrations.
This thesis focuses on three of the most prominent commercially available NPs; ZnO, CeO2 and Ag, and covers all aspects of the application of stable isotope labeling and tracing for these materials. This includes; (i) an assessment and evaluation of the technique for application with CeO2 NPs, including the development of chemical separation and mass spectrometric methods for an environmental tracer study, (ii) the assessment of a synthesis protocol for the production of isotopically labeled Ag NPs, and (iii) two environmental tracer studies to assess the uptake and loss of Zn from ZnO NPs by an estuarine snail and earthworm.