This title appears in the Scientific Report : 2014 

Field Flow Fractionation in Environmental Research: Characterization of natural nanoparticles in a forest stream
Gottselig, Nina (Corresponding Author)
Bol, Roland / Küppers, Stephan / Klumpp, Erwin / Nischwitz, Volker
Analytik; ZEA-3
Agrosphäre; IBG-3
24. Doktorandenseminar des Arbeitskreises Separation Science der GDCh-Fachgruppe Analytische Chemie, Hohenroda (Germany), 2014-01-05 - 2014-01-07
Conference Presentation
Terrestrial Systems: From Observation to Prediction
Modelling and Monitoring Terrestrial Systems: Methods and Technologies
A high precision fractionation of particle size classes between 1nm and 1000nm is best applicable with the techniques of field flow fractionation (FFF). The separation is performed without a stationary phase in an open channel which is subject to a force acting perpendicular to the solvent flow and thus driving the fractionation. For the Asymmetric Flow Field Flow Fractionation (AF4), the sample runs over a membrane with a specific cut-off size perpendicular to which an additional solvent flow acts as the separation field. The fractionation occurs on behalf of diameter, density and diffusion rate of the particles. Every FFF can be coupled to a multitude of detectors serving for particle characterization. The exemplary study aims at characterizing the elemental composition of nanoparticle (NP) fractions in stream water from a forest site and identifying potential source regions. Through coupling of AF4 to ICP-MS, successful measurements of nanoparticle bound iron, aluminum and phosphorus were performed. Two distinct size fractions were observed for all sampling sites: an organic matter- and an iron-determined fraction. For both, concentrations are highest in the midst of the stream with similar low values in the headwaters and near the outlet of the catchment. Elemental ranges for the organic fraction are 0.1 - 5.2µg/l for phosphorus and aluminum and 25 - 680µg/l for iron; for the iron-determined fraction 2 - 26µg/l for P and Al and 340 - 1800µg/l for Fe, respectively. Moreover, between 10-100% of P and Fe concentrations in the samples were bound to particles, in contrast to ~1.5% for Al. Overall, through coupling of FFF and ICP-MS a first assessment of the source regions of nanoparticles in stream water and the distribution of size classes in accordance with the elemental composition could be done.