Patent ID: 6194717
Filing Date: 2001-02-27
Classification: H01J

Abstract:
A method of mass analysis utilizing a quadrupole rod set located in a vacuum chamber, the method comprising:(1) providing a stream of ions and supplying the stream of ions to one end of a first multipole rod set;(2) supply an RF-only voltage to the multipole rod set, whereby the first multipole rod set acts as an ion guide and transmits desired ions therethrough;(3) passing the ions into an analyzing quadrupole rod set;(4) supplying an RF-only voltage to the analyzing quadrupole rod set, whereby desired ions having a mass-to-charge ratio giving a q value of substantially 0.907 gain additional axial kinetic energy upon leaving the analyzing quadrupole rod set;(5) detecting ions leaving the analyzing quadrupole rod set having the increased axial kinetic energy; and(6) selecting the pressure within the first multipole rod set to enhance separation between ions gaining the additional axial kinetic energy and other ions.