Particle analysis in complex environmental systems: Insights gained from single particle ICP-ToF-MS
Goodman, A.*, Ahabchane, H.-E.*, Tardif, Y.*, Iatariene, K.*, Barabash, M.*, Li, Z.*, Hadioui, M.*, Hayes, P.L. and K.J. Wilkinson
Environmental particles are chemically heterogeneous and polydisperse. While bulk measurement techniques are useful for providing information on the overall (average) composition of a sample, they cannot distinguish among individual particle types. For example, a measurement of 0.1% Pb does not allow us to determine whether we have one single pure Pb particle in 1000 or whether the entire population of particles contains 0.1% Pb. Similarly, for a given particle composition, a single 1 µm particle will have similar mass as one million NP (10 nm), but arguably a very different environmental risk. In contrast to the bulk techniques, single particle techniques provide information on both particle size distributions and individual particle compositions, including those of rare, but functionally important particles. We are employing single particle inductively coupled mass spectrometry (SP ICP-MS) and SP ICP-time-of-flight (ToF)-MS to quantify and characterize populations of particles from heterogeneous environmental systems. For both SP-ICP-MS and SP-ICP-ToF-MS, methods will be discussed to lower detection limits and improve extraction efficiencies in diverse environmental matrices (water, soil, biota, air). Examples of applications will be shown to demonstrate the improved understanding that can be obtained from the single particle techniques. Strategies to distinguish anthropogenic from natural particles will be examined. Finally, for inorganic airborne particles, an example will be discussed where the elemental and isotope ratios and the masses of the single particles can be used for dynamically determining the source apportionment of particles produced by industry.
Kevin Wilkinson is a Professor in Environmental Chemistry at the Université de Montréal (UdeM). His research is aimed at gaining a molecular level understanding of contaminant bioavailability and mobility. Professor Wilkinson has established a world-class laboratory at the new Science Campus of the UdeM, where they have extensive and often rare infrastructure (SP QQQ ICPMS, SP high resolution ICPMS, SP TOF ICPMS, analytical ultracentrifugation, dynamic and static light scattering, Coulter particle counter, hydrodynamic chromatography, nanoparticle tracking analysis, darkfield microscopy and fluorescence correlation spectroscopy) for examining particles in different environmental compartments (air, water, snow, soil, biota, sediments). Wilkinson has over 200 publications, over 17,000 citations to his work and an h-index of 72. He is an Associate Editor for Environmental Chemistry (2010- ) and Env. Sci.: Nano (2022- ). In 2018, he won the Canadian Institute of Chemistry-Dima Environmental Research Award.