Extension of the focusable mass range in distance-of-flight mass spectrometry with multiple detectors.

Autor: Gundlach-Graham, Alexander W., Dennis, Elise A., Ray, Steven J., Enke, Christie G., Carado, Anthony J., Barinaga, Charles J., Koppenaal, David W., Hieftje, Gary M.
Zdroj: Rapid Communications in Mass Spectrometry: RCM; Nov2012, Vol. 26 Issue 21, p2526-2534, 9p
Abstrakt: RATIONALE Distance-of-flight mass spectrometry (DOFMS) is a velocity-based mass separation technique in which ions are spread across a spatially selective detector according to m/z. In this work, we investigate the practical mass range available for DOFMS with a finite-length detector. METHODS A glow-discharge DOFMS instrument has been constructed for the analysis of atomic ions. This instrument was modified to accommodate two spatially selective ion detectors, arranged co-linearly, along the mass-separation axis of the analyzer. With this geometry, each detector covers a different portion of the distance-of-flight spectrum and ions are detected simultaneously at the two detectors. The total flight distance covered by the two detectors is 106 mm and simulates DOF detection across a broad mass range. RESULTS DOFMS theory predicts that ions of all m/z values are focused at a single flight time, but at m/z-dependent flight distances. Therefore, ions that are detected across a wide portion of the DOF axis should all yield the same peak widths. With a focal-plane camera detector and a micro-channel plate/phosphor-screen detection assembly, we found simultaneous, uniform focus of 40Ar2+ and of 65Cu+ and 63Cu+ with the ions spread 82 mm across the DOF axis. This detection length, combined with the current instrument geometry, allows for a simultaneously detectable m/z value of 4:3 (high mass-to-low mass). CONCLUSIONS These results are the first experimental verification that constant-momentum acceleration (CMA)-DOFMS provides energy focus across an extended detection length. Evidence presented demonstrates that DOFMS is amenable to detection with (at least) a 100-mm detector surface. These results indicate that DOFMS is well suited for detection of broader mass ranges. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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