visualization-ambient-mass-spectrometry-with-use-schlieren

Visualization of Ambient Mass Spectrometry with the Use of Schlieren Photography

This manuscript outlines how to visualize mass spectrometry ambient ionization sources using schlieren photography. In order to properly optimize the mass ...

University of Maryland, Baltimore County

Water cluster ion intensity and distribution is affected by source conditions in direct sample analysis (DSA) ionization. Parameters investigated in this paper include source nozzle diameter, gas flow rate, and source positions relative to the mass spectrometer inlet. Schlieren photography was used to image the gas flow profile exiting the nozzle. Smaller nozzle diameters and higher flow rates produced clusters of the type [H + (H(2)O)(n)](+) with greater n and higher intensity than larger nozzles and lower gas flow rates. At high gas flow rates, the gas flow profile widened compared with the original nozzle diameter. At lower flow rates, the amount of expansion was reduced, which suggests that lowering the flow rate may allow for improvements in sampling spatial resolution.

Characterization of a Direct Sample Analysis (DSA) Ambient Ionization Source.

Molecular ionization-desorption analysis source (MIDAS), which is a desorption atmospheric pressure chemical ionization (DAPCI) type source, for mass spectrometry has been developed as a multi-functional platform for the direct sampling of surfaces. In this article, its utility for the analysis of thin-layer chromatography (TLC) plates is highlighted. Amino acids, which are difficult to visualize without staining reagents or charring, were detected and identified directly from a TLC plate. To demonstrate the full potential of MIDAS, all active ingredients from an analgesic tablet, separated on a TLC plate, were successfully detected using both positive and negative ion modes. The identity of each of the compounds was confirmed from their mass spectra and compared against standards. Post separation, the chemical signal (blue permanent marker) as reference marks placed at the origin and solvent front were used to calculate retention factor (Rf) values from the resulting ion chromatogram. The quantitative capabilities of the device were exhibited by scanning caffeine spots on a TLC plate of increasing sample amount. A linear curve based on peak are, R2 = 0.994, was generated for seven spots ranging from 50 to 1000 ng of caffeine per spot.

Article	Year
Characterization of a Direct Sample Analysis (DSA) Ambient Ionization Source. Journal of the American Society for Mass Spectrometry\| PubMed ID: 26091890	2015
Molecular Ionization-Desorption Analysis Source (MIDAS) for Mass Spectrometry: Thin-Layer Chromatography. Journal of the American Society for Mass Spectrometry\| PubMed ID: 26471042	2016

Gregory T. Winter

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