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