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14 May 1992 Laser-desorption tandem time-of-flight mass spectrometry with continuous liquid introduction
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A new method to combine aqueous sample introduction with matrix assisted laser desorption mass spectrometry (MS) for interfacing liquid-chromatographic techniques, such as capillary electrophoresis, to MS is described. Aqueous sample solution is introduced directly into the ion source of a time-of-. flight (TOF) mass spectrometer through a fused silica capillary; evaporative cooling results in ice formation at the end of the capillary. The ice can be made to extrude continuously by using localized resistive heating. With direct laser desorption, molecular ions from proteins as large as bovine insulin (5734 Da) can be produced. Two-step desorption/photoionization with a variety of wavelengths is demonstrated, and has the advantages of improved resolution and shot-to-shot reproducibility. Ion structural information is obtained using surface-induced dissociation with an in-line collision device in the reflectron mirror of the TOF instrument. Product ion resolution of ~70 is obtained at m/z77. Extensive fragmentation can be produced with dissociation efficiencies between 7-15% obtained for molecular ions of small organic molecules. Efficiencies approaching 30% are obtained for larger peptide ions.
© (1992) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Evan R. Williams, Glenn C. Jones Jr., LiLing Fang, Takeshi Nagata, and Richard N. Zare "Laser-desorption tandem time-of-flight mass spectrometry with continuous liquid introduction", Proc. SPIE 1636, Applied Spectroscopy in Materials Science II, (14 May 1992);


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