Mass dependence of time-lag focusing in time-of-flight mass spectrometry—an analysis

• Published in: International journal of mass spectrometry and ion processes 1990-04, Vol.97 (1), p.87-106
• Main Authors: Erickson, Eric D., Yefchak, George E., Enke, Christie G., Holland, John F.
• Format: Article
• Language: English
• Subjects: Atomic and molecular physics; Electronic structure of atoms, molecules and their ions: theory; Exact sciences and technology; Other topics in the theory of the electronic structure of atoms, molecules and their ions; Physics
• ISSN: 0168-1176; 1873-2801
• DOI: 10.1016/0168-1176(90)85041-Y

When using mass spectral detection strategies in which wide ranges of m/z values are monitored, it is important for ions of all masses of interest to be in focus during the data collection interval. In conventional time-of-flight mass spectrometry of gaseous samples using dual field source extraction for spatial compensation, ion focus is a function of the time lag and the mass-to-charge ratio of the ion. The mass dependence of ion focus in a CVC 2000 time-of-flight mass spectrometer has been studied using a computer simulation in order to determine the mass ranges over which the losses in mass resolution and peak intensity are acceptable. As few as three different values of time lag are required to cover the m/z range from 50 to 700 u. Selection of optimum extraction voltages involves a trade-off between the width of the mass windows for any given time lag setting and the total mass range available with unit-mass-resolution.