Analytical Characterization of Ice-Nucleating Particles from Birch Trees

Heterogeneous ice nucleation plays a crucial role in diverse processes in our environment from ice cloud formation in the atmosphere, affecting the radiation balance of our planet, to frost damage protection of various plants and animals down on Earth. Substances triggering heterogeneous ice nucleation are called ice-nucleating particles (INP) and can be of various origins. Since 2001 it is known that birch pollen act as efficient INP (Diehl et al. 2001). Recent results from our working group show that the INP are not bound to the surface of the pollen but are rather macromolecular components, which are easily released from the pollen surface into water (Pummer et al. 2012). As pollen are seasonal, we investigated other parts of birch trees, to clarify the ability of birch trees to act as INP sources. We found INP throughout the tree, which match the behavior of the INP released from pollen, indicating a relationship (Felgitsch et al. 2017). In order to elucidate the chemical structure from above mentioned INP we applied an array of orthogonal analytical techniques/strategies including solid phase extraction, centrifugal filtration, capillary zone electrophoresis, high performance liquid chromatography - electrospray ionisation - mass spectrometry and multistage - mass spectrometry.

Diehl, K., C. Quick, S. Matthias-Maser, S. K. Mitra, and R. Jaenicke. 2001. 'The ice nucleating ability of pollen Part I : Laboratory studies in deposition and condensation freezing modes', Atmospheric Research, 58: 75-87.

Felgitsch, L., P. Baloh, J. Burkart, M. Mayr, M. E. Momken, T. M. Seifried, P. Winkler, D. G. Schmale III, and H. Grothe. 2017. 'Birch leaves and branches as a source of ice-nucleating macromolecules', Atmospheric Chemistry and Physics Discussions: 1-22.

Pummer, B. G., H. Bauer, J. Bernardi, S. Bleicher, and H. Grothe. 2012. 'Suspendable macromolecules are responsible for ice nucleation activity of birch and conifer pollen', Atmospheric Chemistry and Physics, 12: 2541-2550.