The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 09, 1997
Filed:
May. 20, 1996
Vladimir M Doroshenko, Reisterstown, MD (US);
Robert J Cotter, Baltimore, MD (US);
The Johns Hopkins University, Baltimore, MD (US);
Abstract
A method of operation of an ion trap mass spectrometer which isolates a first group of ions having a mass-to-charge ratio range is disclosed. The method includes producing ions from a plurality of atoms or molecules; trapping the ions in an ion trap by applying a trapping voltage to a ring electrode; applying an excitation voltage to a pair of end-cap electrodes; employing as the excitation voltage a first broadband excitation waveform and a second broadband excitation waveform, with the first waveform exciting the ions excluding substantially all of the first group and also excluding substantially all of a second group of ions having a range of mass-to-charge ratios about the first group's mass-to-charge ratio range, and the second waveform exciting the second group; applying the first waveform in order to eject the ions excluding substantially all of the first and second groups; and applying the second waveform in order to successively eject the second group of ions, according to the mass-to-charge ratios thereof, excluding substantially all of the first group of ions, thereby isolating the first group of ions. In another embodiment, the excitation voltage is a broadband excitation waveform having first, second, and third excitation portions, with the first and third portions exciting the ions excluding substantially all of the first group and also excluding substantially all of the second group, and the second portion exciting the second group. Associated apparatus is also disclosed.