Applications of 1.06-micron IR laser desorption on a Fourier transform mass spectrometer.
Various sugars, peptides, and lipids were analyzed on a Fourier transform mass spectrometer using laser desorption and ionization with and without the assistance of matrixes. A compact Nd:YAG laser with an output at 1.06 microns corresponding to fundamental frequency was employed. Gram-negative and Gram-positive bacteria were also subjected to laser desorption mass spectrometry. Characteristics ions of conjugated lipid, formed by attachment of alkali metal cations, endogenous to the cells, were observed. Particle/liquid matrixes (e.g., cobalt in glycerol) proved to be useful with the 1.06-micron laser. The particles absorb efficiently laser radiation in a broad wavelength range. The liquid provides the same advantages as in fast atom bombardment: increased signal-to-noise ratios and enhanced sample lifetimes. The effect of laser power on total ion current was shown to differ for samples with and without the particle/liquid matrix. The Fourier transform analyzer provides MS/MS capability for both positive and negative ions from complex mixtures. Ions desorbed externally are introduced into the cell via a quadrupole ion guide with a lower mass cutoff. Such a setup allows matrix ions to be excluded and thus provides excellent signal-to-noise ratios for lower mass range fragment ions formed inside the cell.
Ho
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YP
Department of Chemistry and Biochemistry, University of Maryland, College Park 20742, USA.
Fenselau
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C
D001407:Bacillus / Q000737:chemistry; D004885:Erwinia / Q000737:chemistry; D007834:Lasers; D008970:Molecular Weight; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D013373:Substance P / Q000737:chemistry
D013373:Substance P