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C. Herzig, J. Frank, M. Morgenbesser, A.K. Opitz, J. Fleig, A. Limbeck:
"Online LASIL Combined with ICP-OES Detection for the Analysis of Complex Metal Oxide Thin Films";
Talk: 14. ASAC JunganalytikerInnen - Forum, Wien; 2018-05-04 - 2018-05-05.

Complex metal oxides such as SrTiO3 (STO) or La0,58Sr0,40Co0,20Fe0,80 (LSCF) are of great interest as new materials for electrochemical devices. Investigating these materials with a view to their electrochemical properties also includes determining the stoichiometry due to a strong link between stoichiometry and electrochemical properties. For solid samples like thin films laser ablation - inductively coupled plasma -mass spectrometry (LA-ICP-MS) can be the method of choice. This method comes with several advantages like the possibility for the analysis of depth profiles or lateral distribution maps. Although there is one major drawback: Quantification of the derived signals is complex. Due to matrix effects in the ablation step and the ionization in the plasma, matrix matched standards are obligatory.
Recently we presented a new approach to make quantification of signals gained by laser ablation easier: In our approach the particles produced in the ablation step are transported by a carrier liquid (e.g. water) and not by a carrier gas like He or Ar to the detection system (ICP-MS/ICP-OES). For analysis the solid sample is submerged into the liquid during the ablation step and the nanoparticles produced during the ablation event were directed to the element specific detection device; therefore this technique is called online LASIL (Laser Ablation of Solids in Liquid). One major advantage of this approach is the possibility to use certified liquid standards for the calibration, because the nanoparticle suspension yielded with this technique can be treated as liquid solutions. With this procedure the advantages of the classical liquid measurement and the solid sampling method can be combined. First results of coupling the LASIL technique with the ICP-OES have been published by Bonta et al.
In this contribution we present further improvements of the online LASIL system gaining a broader knowledge of the system's behavior. For example the washout characteristic of the in-house built ablation cell could be drastically improved by using a discontinuous flow of the liquid transport medium. This development caused a higher signal intensity and a better reproducibility. Due to these progresses, determining the stoichiometry of CMOs with minor dopant concentrations becomes possible.