Mass spectrometry imaging with laser-induced postionization.
Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) can simultaneously record the lateral distribution of numerous biomolecules in tissue slices, but its sensitivity is restricted by limited ionization. We used a wavelength-tunable postionization laser to initiate secondary MALDI-like ionization processes in the gas phase. In this way, we could increase the ion yields for numerous lipid classes, liposoluble vitamins, and saccharides, imaged in animal and plant tissue with a 5-micrometer-wide laser spot, by up to two orders of magnitude. Critical parameters for initiation of the secondary ionization processes are pressure of the cooling gas in the ion source, laser wavelength, pulse energy, and delay between the two laser pulses. The technology could enable sensitive MALDI-MS imaging with a lateral resolution in the low micrometer range.
Institute for Hygiene, University of Münster, Robert-Koch-Strasse 41, 48149 Münster, Germany.
Jens
J
Soltwisch
Institute for Hygiene, University of Münster, Robert-Koch-Strasse 41, 48149 Münster, Germany. Interdisciplinary Center for Clinical Research (IZKF), University of Münster, Domagkstrasse 3, 48149 Münster, Germany.
Hans
H
Kettling
Institute for Hygiene, University of Münster, Robert-Koch-Strasse 41, 48149 Münster, Germany. Interdisciplinary Center for Clinical Research (IZKF), University of Münster, Domagkstrasse 3, 48149 Münster, Germany.
Simeon
S
Vens-Cappell
Institute for Hygiene, University of Münster, Robert-Koch-Strasse 41, 48149 Münster, Germany.
Marcel
M
Wiegelmann
Institute for Hygiene, University of Münster, Robert-Koch-Strasse 41, 48149 Münster, Germany.
Johannes
J
Müthing
Institute for Hygiene, University of Münster, Robert-Koch-Strasse 41, 48149 Münster, Germany. Interdisciplinary Center for Clinical Research (IZKF), University of Münster, Domagkstrasse 3, 48149 Münster, Germany. klaus.dreisewerd@uni-muenster.de.
Klaus
K
Dreisewerd
D000818:Animals; D002241:Carbohydrates / Q000032:analysis / Q000737:chemistry*; D002531:Cerebellum / Q000737:chemistry; D005260:Female; D005732:Gangliosides / Q000032:analysis / Q000737:chemistry; D007477:Ions; D007834:Lasers; D008055:Lipids / Q000032:analysis / Q000737:chemistry*; D008297:Male; D027845:Malus / Q000737:chemistry; D008563:Membrane Lipids / Q000032:analysis / Q000737:chemistry; D008810:Mice, Inbred C57BL; D011522:Protons; D011917:Rats, Inbred Lew; D012671:Seminiferous Tubules / Q000737:chemistry; D012995:Solubility; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000295:instrumentation / Q000379:methods*; D013552:Swine; D014815:Vitamins / Q000032:analysis / Q000737:chemistry*
D002241:Carbohydrates; D005732:Gangliosides; D007477:Ions; D008055:Lipids; D008563:Membrane Lipids; D011522:Protons; D014815:Vitamins