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Updated: May 17, 2026
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Induction of Microstreaming by Nonspherical Bubble Oscillations in an Acoustic Levitation System
Published on: May 9, 2021
CO2 laser ionization of acoustically levitated droplets
Arne Stindt1, Merwe Albrecht, Ulrich Panne
1BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Str. 11, 12489 Berlin, Germany.
Analytical and Bioanalytical Chemistry
|November 8, 2012
Summary
This study presents a novel method combining ultrasonic levitation and infrared matrix-assisted laser desorption/ionization mass spectrometry for contactless liquid analysis. The technique enables reproducible mass spectrometric detection, particularly for microfluidics applications.
Area of Science:
- Analytical Chemistry
- Mass Spectrometry
- Physical Chemistry
Background:
- Direct laser ionization of liquids is crucial for various analytical applications.
- Existing methods for liquid sample analysis, including supported droplets and free jets, lack detailed mechanistic understanding of ion formation.
- A need exists for contactless and reproducible methods for liquid sample ionization and analysis.
Purpose of the Study:
- To introduce a novel method combining ultrasonic levitation with infrared matrix-assisted laser desorption/ionization (IR-MALDI) mass spectrometry.
- To investigate the contactless confinement and vaporization of liquid droplets for mass spectrometric analysis.
- To elucidate the ion formation mechanism in this new analytical setup.
Main Methods:
- Development of a homebuilt ultrasonic levitator for contactless confinement of liquid droplets (several millimeters in diameter).
- Vaporization of droplets using a carbon dioxide laser near the atmospheric pressure interface of a time-of-flight mass spectrometer.
- High repetition rate shadowgraphy experiments to study the evaporation process and vapor confinement by the ultrasonic field.
Main Results:
- Demonstration of contactless confinement and controlled vaporization of liquid samples using ultrasonic levitation and CO2 laser.
- Shadowgraphy revealed ballistic evaporation and strong vapor confinement by the ultrasonic trap.
- Acquisition of typical mass spectra for glycerol/water matrix and lysine, with and without trifluoroacetic acid, showcasing the technique's capability.
Conclusions:
- The combined ultrasonic levitation and IR-MALDI MS technique offers a promising approach for reproducible mass spectrometric detection of liquid samples.
- The method is particularly suitable for microfluidics applications, addressing the need for contactless and controlled sample handling.
- Further investigation into the ionization mechanism can optimize the detection of various analytes.
