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:
Aug. 01, 1995
Filed:
May. 19, 1994
Bruker-Franzen Analytik GmbH, , DE;
Abstract
A method and a device for the mass selective excitation of the secular oscillations of selected ion types in an RF quadrupole ion trap, including the simultaneous excitation of more than one ion type, is disclosed. The secular oscillation frequency is excited by resonances with specific frequencies of the frequency bands of the additional alternating fields, the frequency bands being generated digitally at a basic pulse rate .OMEGA.. Interfering frequency side bands .OMEGA.-.omega., .OMEGA.+.omega., 2.OMEGA.-.omega., 2.OMEGA.+.omega., etc. arise, however, for each frequency .omega. within the frequency bands. These side bands can excite and eliminate other ions, which are not to be eliminated, in an undesired manner. The invention comprises forming the side bands in such a way that they only excite the selected ions. This is done by making the basic pulse rate for digital generation of the frequency bands for the additional alternating voltage identical with the frequency of the drive voltage of the ion trap or with an integral multiple of it and coupling the basic pulse rate to it in locked phase relation.