Laser desorption VUV postionization MS imaging of a cocultured biofilm

Laser desorption postionization mass spectrometry (LDPI-MS) imaging is demonstrated with a 10.5 eV photon energy source for analysis and imaging of small endogenous molecules within intact biofilms. Biofilm consortia comprised of a synthetic Escherichia coli K12 coculture engineered for syntrophic m...

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Veröffentlicht in:Analytical and bioanalytical chemistry 2013-09, Vol.405 (22), p.6969-6977
Hauptverfasser: Bhardwaj, Chhavi, Moore, Jerry F., Cui, Yang, Gasper, Gerald L., Bernstein, Hans C., Carlson, Ross P., Hanley, Luke
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Sprache:eng
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Zusammenfassung:Laser desorption postionization mass spectrometry (LDPI-MS) imaging is demonstrated with a 10.5 eV photon energy source for analysis and imaging of small endogenous molecules within intact biofilms. Biofilm consortia comprised of a synthetic Escherichia coli K12 coculture engineered for syntrophic metabolite exchange are grown on membranes and then used to test LDPI-MS analysis and imaging. Both E. coli strains displayed many similar peaks in LDPI-MS up to m/z 650, although some observed differences in peak intensities were consistent with the appearance of byproducts preferentially expressed by one strain. The relatively low mass resolution and accuracy of this specific LDPI-MS instrument prevented definitive assignment of species to peaks, but strategies are discussed to overcome this shortcoming. The results are also discussed in terms of desorption and ionization issues related to the use of 10.5 eV single-photon ionization, with control experiments providing additional mechanistic information. Finally, 10.5 eV LDPI-MS was able to collect ion images from intact, electrically insulating biofilms at ∼100 μm spatial resolution. Spatial resolution of ∼20 μm was possible, although a relatively long acquisition time resulted from the 10 Hz repetition rate of the single-photon ionization source. Figure Neutral species laser desorbed from cocultured biofilms undergo single photon ionization by VUV radiation and resultant ions are detected by time-of-flight mass spectrometry
ISSN:1618-2642
1618-2650
DOI:10.1007/s00216-012-6454-0