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S. Hossein-Zadegan, W. Nischkauer, M.-A. Néouze, A. Limbeck:
"FI-ICP-OES Determination of Rare Earth Elements in Environmental Samples Using Dispersed Particle Extraction with Surface Functionalized Magnetic Nanoparticles";
Talk: 5^th EuCheMS Chemistry Congress, Istanbul, Turkey; 2014-08-31 - 2014-09-04; in: "5th EuCheMS Chemical Congress - Abstracts", (2014), 512 pages.

Differences in local abundance of rare earth elements (REEs) provide the possibility for geochemical fingerprints used, e.g. in oil extraction missions. Due to increased anthropogenic emissions of REEs, also investigation regarding the toxicity of these elements have gained more interest lately. However, it is necessary to enrich these naturally low concentrated elements to gain high sensitivity and selectivity of spectrometry´s methods such as ICP-OES or ICP-MS. Solid phase extraction (SPE) is the most commonly applied enrichment procedure, but because of acclaimed disadvantages with the use of SPE columns, we recently introduced an improved method called dispersed particle extraction (DPE). With DPE, there is no need to elute the adsorbed REE cations from the SPE sorbent material using strong solvents. Instead, the slurry of adsorbed analytes on functionalized sub-micron silica particles is directly introduced into the plasma. Thus, higher recoveries and less variability in results were achieved.
In the here presented contribution, we propose a flow-injection (FI) system with ICP-OES detection for on-line determination of REEs in aqueous solutions using magnetic particles in combination with DPE. Silica coated cobalt nanoparticles with sulfonyl groups on their surface are suspended into the pH-adjusted sample digests. REEs are thereby retained on the functionalized particles. With the use of a FI-system, a defined volume of sample slurry is introduced into a strong magnetic field, where the analyte-loaded particles are trapped. After replacing the sample solution by a rinse solution, the collected particles are promptly released and the nanoparticles including the adsorbed REEs are introduced into the ICP-OES. Thus, a separation of sample matrix and analytes is possible, accompanied by a significant pre-concentration. The developed procedure has been applied for the determination of REEs in different environmental samples.

FI-ICP-OES, magnetic nanoparticles, trace metal analysis

Project Head Andreas Limbeck:
Nanoparticles for improved trace metal analysis