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F. Horak, A. Nagl, K. Föttinger, A. Limbeck:
"Quantitative analysis of surface modified nano-particle catalyst materials using LA-ICP-MS";
Poster: 14th European Workshop on Laser Ablation, Pau, France; 26.06.2018 - 29.06.2018; in: "Book of Abstracts", (2018), S. 50.

TiO2 nanoparticles (NP) are commonly used in a large variety of products ranging from paints, coatings and plastics to pharmaceuticals and cosmetics, as well as substrate for catalyst materials. The catalytic properties of NP are closely linked to their chemical/elemental composition and surface modification, where even small variations can result in drastic changes to the performance. Therefore, an accurate determination of the elemental composition is an integral part in the characterization of such advanced materials. For this purpose sample pretreatment procedures such as acid digestion, fusion or dry ashing are commonly used in combination with subsequent liquid analysis. These methods are well established but require a signi cant investment in sample handling and provide only information on the average composition of the material. Here, we propose a novel solid sampling approach which enables quantitative analysis of surface modi ed TiO2 NP based on Laser Ablation Inductive Coupled Plasma Mass Spectrometry (LA-ICP-MS).
Catalyst suspensions were spread on a polycarbonate disc and ablated with a NWR213 laser-ablation system hyphenated to a Thermo Fisher iCap Q ICP-MS, after evaporation of the solvent. Calibration curves from single element as well as mixed element in-house reference material were prepared using a micro-dried-droplet (µDD) method on matching substrate material. The obtained results were compared to conventional wet chemical methods.
The presented method proved to be simple in terms of sample handling and allowing quick analysis cycles whilst achieving similar precision as wet chemistry methods. Furthermore, statistical information about the homogeneity of the dopant concentration was achieved due to the signi cant smaller sampling size compared to conventional methods. The µDD method proved to be a versatile approach for the quantification of single particles with varying composition.

LA-ICP-MS, nanoparticle analysis, elemental composition, µ-dried droplets