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W. Nischkauer, A. Izmer, M.-A. Néouze, F. Vanhaecke, A. Limbeck:
"Determination of Platinum group elements (Pt, Pd, Rh) in urban PM10 samples via dispersed particle extraction followed by dried-droplet Laser-Abaltion ICP-MS";
Vortrag: 2014 Winter Conference on Plasma Spectrochemistry, Amelia Island, Florida, US; 06.01.2014 - 11.01.2014; in: "2014 Winter Conference Program and Abstracts", (2014), ISSN: 0161-6951; 360 S.

The uptake of metals via the respiratory tract has lately gained more and more interest and especially the particulate matter fraction of 10 µm diameter or less (PM10) is in the focus of medical investigation due to its ability to directly enter the lung and not being retained by physiological filter systems (e.g., the mucous membrane). Besides elements or compounds that exhibit well-known adverse health effects (e.g., Pb, Cd, silica), the presence of Platinum Group Elements (PGEs) in respirable traffic-induced dust and airborne particulate matter requires closer monitoring, especially since toxicological knowledge on these elements is still limited and the emission of PGEs has significantly increased during the last decades due to the use of automotive catalyst systems.
This is however not a trivial task since the determination of PGEs in environmental matrices is hampered by their low abundance (usually only ng g-1 levels) which calls for very sensitive analysis via, e.g., ICP-MS. However, even using ICP-MS, reliable determination is not self-evident as a result of the high excess of elements that can be sources for, e.g., polyatomic interferences in ICP-MS analysis (e.g., Zn, Cu, Sr). Since some of these interferences persist even in high resolution ICP-MS, chemical isolation of the target analytes is mandatory.
In this contribution, we present a novel combination of a sample pre-treatment strategy (Dispersed Particle Extraction, an approach developed in our laboratories) with a solid sampling technique (Laser Ablation) in order to allow for an enhanced determination of PGEs in urban PM10 samples.
To this end, digested PM10 samples were first pre-treated using a modified Dispersed Particle Extraction procedure. PGE-chlorocomplexes are retained on sub-µm sorbent particles with highly porous surface equipped with Strong Anionic Exchanger functionalities. Once the analytes are immobilized on the resin, the sorbent material is mechanically separated from the surrounding sample solution via centrifugation, washed and collected in a small volume of diluted acid. The sorbent material is finally dissolved to obtain a clear solution. Since the retention is selective, a very good removal of concomitant matrix elements is possible.
For analysis, the solution obtained after Dispersed Particle Extraction was applied on polymer targets, dried and analyzed via Laser Ablation ICP-MS which offers the benefit of dry plasma conditions that further reduce oxide-based interferences.
The developed approach offers an effective way for the removal of matrix elements and yields good sensitivity due to the pre-concentration obtained during the initial sample pre-treatment and due to the high sample introduction efficiency achieved by the Laser Ablation system. These improvements in sensitivity and selectivity allowed the analysis of PM10 samples collected during sampling intervals shorter than the usually applied 24 hours.

Dispersed particle extraction, Dried droplet analysis, LA-ICP-MS, Platinum group elements