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Characterisation of levitated samples for modelling of condensed matter

  • Many of today’s analytical problems are characterized by small sample volumes and can only be solved through a corresponding miniaturisation of the analytical instrumentation. Handling of small-sample volumes is inherently difficult due to contamination and sorption processes on the walls of containers. Acoustic levitation is a powerful tool for contact-free sample handling of solid, liquid, and selected gaseous samples. In addition, levitation permits a chemical pre-treatment such as enrichment, extraction, and derivatisation as well as combination with other analytical techniques such as optical spectroscopy. Acoustically levitated liquid and solid samples are typically in a range between 0.005-5 µl (diameter 0.2-2 mm respectively) and are suspended in a gaseous environment by a stationary ultrasonic field. Acoustic levitation avoids sample contamination and sorption processes by container walls, but suffers from evaporation and loss of solvents. Nonetheless, it is ofMany of today’s analytical problems are characterized by small sample volumes and can only be solved through a corresponding miniaturisation of the analytical instrumentation. Handling of small-sample volumes is inherently difficult due to contamination and sorption processes on the walls of containers. Acoustic levitation is a powerful tool for contact-free sample handling of solid, liquid, and selected gaseous samples. In addition, levitation permits a chemical pre-treatment such as enrichment, extraction, and derivatisation as well as combination with other analytical techniques such as optical spectroscopy. Acoustically levitated liquid and solid samples are typically in a range between 0.005-5 µl (diameter 0.2-2 mm respectively) and are suspended in a gaseous environment by a stationary ultrasonic field. Acoustic levitation avoids sample contamination and sorption processes by container walls, but suffers from evaporation and loss of solvents. Nonetheless, it is of great impact for the characterization of small samples. Exact determination of volume is inherently important to find out the resultant concentration in evaporating droplets. Levitation is a possibility to characterise the starting conditions of crystallisation and polymerisation. Even for spectroscopic methods the correct information on shape, size and concentration of samples are indispensable. To determine the size and volume of levitated samples, different methods of contactless droplet size monitoring were developed and compared in detail. They give the initial values for modelling of evaporation effects. In addition, for balancing evaporation and condensation on levitated drops during the experiments, non-contact techniques of solvent and reagent supply have been tested. Here, the advantages of acoustic levitation are demonstrated for on line analysis of crystallisation in a levitated droplet. The evaporation and formation of crystals is observed via time-resolved X-ray diffraction using synchrotron radiation at BESSY. Wall-free crystallisation in an acoustic levitator gives a tool to prove existing models concerning crystallisation processes. Furthermore the occurrence of polymorphic modifications depending on different conditions can be detected in situ under different and adjustable conditions.zeige mehrzeige weniger

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Metadaten
Autor*innen:Jork Leiterer
Koautor*innen:Franziska Emmerling, Andreas Thünemann, Ulrich Panne
Dokumenttyp:Posterpräsentation
Veröffentlichungsform:Präsentation
Sprache:Englisch
Titel des übergeordneten Werkes (Englisch):13. Vortragstagung "Modellierung in der Festkörper- und Materialchemie" der GDCh-Fachgruppe Analytische Chemie, Rheinisch-Westfälische Technische Hochschule Aachen
Jahr der Erstveröffentlichung:2006
Veranstaltung:13. Vortragstagung "Modellierung in der Festkörper- und Materialchemie" der GDCh-Fachgruppe Analytische Chemie, Rheinisch-Westfälische Technische Hochschule Aachen
Veranstaltungsort:Aachen, Germany
Beginndatum der Veranstaltung:2006-09-20
Enddatum der Veranstaltung:2006-09-22
Verfügbarkeit des Dokuments:Datei im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:19.02.2016
Referierte Publikation:Nein
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