Acoustic levitation in the field of analytical, physical, and atmospheric chemistry

In this contribution an overview of fundamentals, possibilities, and applications of acoustic levitation in the field of analytical, physical, and atmospheric chemistry investigated by Neidhart and co-workers since the 1990s will be given. Started with sample preparation procedures in acoustically levitated drops, e.g., analytical enrichment, liquid–liquid extraction, and acid-base titration [E. Welter and B. Neidhart, Fresenius J. Anal. Chem. 357, 345–350 (1997); R. Eberhard and B. Neidhart, ibid. 365, 475–479 (1999); O. Rohling, C. Weitkamp, and B. Neidhart, ibid. 368, 125–129 (2000)], the work has been continued in evaporation processes of liquids [R. Tuckermann, S. Bauerecker, and B. Neidhart, Analytical Bioanal. Chem. 372, 122–127 (2002)], crystallization, and freezing processes in acoustically levitated drops, formation and characterization of monomolecular films on the surface of levitated drops, formation and growth of particles [S. Bauerecker and B. Neidhart, J. Chem. Phys. 109(10), 3709–3712 (1998); Science 282, 2211–2212 (1998)] and trapping of heavy gases [R. Tuckermann, B. Neidhart, E. G. Lierke, and S. Bauerecker, Chem. Phys. Lett. 363, 249–354 (2002)] in stationary ultrasonic fields. Examples and results of these investigations will be presented.