Patent ID: 8481926
Filing Date: 2013-07-09
Classification: H01J

Abstract:
1. A method for filtering ions in a mass spectrometer, said mass spectrometer comprising an ion guide, a quadrupole mass filter, a collision cell and a time of flight (ToF) detector, said mass spectrometer enabled to transmit an ion beam through to said ToF detector, the method comprising: operating said mass spectrometer in MS mode, such that ions in said ion beam remain substantially unfragmented, said quadrupole mass filter operating at a pressure substantially lower than in either of said ion guide and said collision cell; operating said quadrupole mass filter in a bandpass mode such that ions outside of a range of interest are filtered from said ion beam, leaving ions inside said range of interest in said ion beam, wherein a low mass boundary and a high mass boundary of said range of interest are defined by independently adjusting an RF voltage and a DC voltage applied to said quadrupole mass filter; and analyzing said ions inside said range of interest at said ToF detector and coordinating a width of said range of interest with overpulsing ToF extraction to increase a duty cycle of said mass spectrometer.