Investigation of matrix effects in liquid analyses by ICP-OES/MS applying mono-disperse droplet injection

• Applicant: Professor Dr. Kay Niemax, since 1/2010
• Subject Area: Analytical Chemistry
• Term: from 2009 to 2012
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 156961280

Matrix effects known from analyses of liquid samples using inductively coupled plasma-optical emission as well as mass spectrometry (ICP-OES/MS) are investigated experimentally. For this purpose, monodisperse droplets with diameters between ~30 and ~65 µm generated by commercial droplet dispensers are injected into the ICP. The processes of desolvation, atomization and ionization are observed with high temporal resolution recording simultaneously line intensities of atoms and ions belonging to the analytes and the solvent. In particular, the energy transfer between collision partners from the atomized and ionized droplets and the spatial and temporal effects on the local plasma parameters are of interest. The plasma sub-volumes where the interactions occur are imaged with adapted magnification onto the entrance slit of ICCD-spectrometers in order to measure also the spatial expansion of excited atoms and ions from atomized droplets during their passage through the ICP. The investigation will help to understand the physics of matrix effects so that strategies can be developed to reduce or even overcome matrix effects in ICP-OES/MS of liquid samples.In comparison with current nebulizer types, sample introduction by droplet generators has 100% efficiency and is, therefore, suitable for analyses of pL sample volumes. Moreover, it will be investigated whether the periodic introduction of monodisperse droplets can improve the analytical figures of merit of ICP-OES/MS in comparison with current nebulizers where droplets of different sizes are simultaneously injected to the ICP.The project will be carried out in very close collaboration with Prof. Gary M. Hieftje and Dr. George C.Y. Chan (both Department of Chemistry, Indiana University, Bloomington, USA) who are working also on projects for better understanding of matrix effects in ICP-spectrometry of liquid samples in order to optimize the measurement strategy. The main interest of the partners in Bloomington are on macroscopic matrix effects while microscopic processes are in the focus of the ISAS experiments.

• DFG Programme: Research Grants
• International Connection: USA
• Participating Person: Professor Dr. Gary M. Hieftje
• Ehemalige Antragstellerin: Dr. Carmen Cecilia Garcia Perez, until 1/2010