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A. Limbeck, S Rovelli, W. Nischkauer, D Cavallo:
"LA-ICP-MS analysis of size segregated ultrafine airborne particulates";
Talk: 2017 Euopean Winter Conference on Plasma Spectrochemistry, Sankt Anton, Arlberg; 02-19-2017 - 02-24-2017; in: "Book of Abstracts", (2017), 121.

For assessment of adverse health effects of toxic metals present in airborne particulate matter (APM) usually the size fractions below 10 µm and 2.5 µm aerodynamic diameter are considered (PM10 and PM2.5, respectively). However, for ultrafine particles (UFP) an enhanced toxicity is expected since the respiratory deposition is distinctly increased when compared to larger particles, which are separated to a bigger part in the in the pharyngeal and tracheal region. In contrast to PM2.5 and PM10, only few studies report metal contents in the size fraction below 1 µm; problems in analysis due to restricted sample amounts and the complex composition of APM being the main limitations.
This contribution presents an innovative approach for quantitative LA-ICP-MS analysis of size segregated APM samples. A 13-stage low pressure impactor (DLPI) was used for the collection of size-segregated UFP at an urban background site in Como (Italy). Particles ranging from 0.03 to 10 µm were deposited on high-purity polycarbonate as sampling substrate. For analysis, a representative number of sample spots from each impactor stage was analyzed using line scan patterns, which enabled quantitative ablation of the investigated sample spots with sizes ranging from less than 100 to more than 1 mm diameter. Quantification of derived transient signals was accomplished using dried-droplets of aqueous standard solutions; analysis has been performed using the LA-ICP-MS procedure developed for measurement of UFP samples. For method validation, one set of impactor samples was additionally measured using conventional ICP-MS analysis after complete sample mineralization with a mixture of different acids. Accuracy of this standard approach was demonstrated by analysis of NIST SRM 1648a (urban particulate matter). Comparison of ICP-MS results with the data acquired using the proposed LA-ICP-MS procedure revealed an excellent agreement. Finally, the procedure was applied for analysis of an extended set of UFP samples providing information about the seasonal variation of selected trace elements.

LA-ICP-MS, ultrafine particles, quantitative analysis