Patent ID: 8969797
Filing Date: 2015-03-03
Classification: H01J

Abstract:
1. An MS/MS type mass spectrometer equipped with a first mass separating part for selecting ions having a specific mass-to-charge ratio as precursor ions from among various ions, a collision cell for splitting said ions by causing said precursor ions to collide with a prescribed gas, said collision cell having an ion guide for converging and transporting ions with a high-frequency electric field, a second mass separating part for selecting ions having a specific mass-to-charge ratio from among various product ions produced by the splitting of said precursor ions, and a detector for detecting the product ions selected by said second mass separating part, said MS/MS type mass spectrometer being provided with: a) a lens electrode having an ion-passing opening provided on at least one of the inlet side and outlet side of said collision cell; b) a voltage application means for applying a pulse voltage to the lens electrode on said inlet side and/or said outlet side for attracting or repelling said ions in said collision cell; and c) a control means which controls said voltage application means so as to generate the pulse voltage during a suspension period in which the convergence of detection data by said detector is suspended in step with the switching of the mass-to-charge ratio of precursor ions in said first mass separating part, and generate the pulse voltage at a point when a prescribed delay time has passed after the starting point of said suspension period and regulates the length of said delay time according to the length of said suspension period; wherein the delay time is regulated so that a time from termination of application of the pulse voltage to termination of the suspension period is set in advance to at least a prescribed value, the prescribed value set to a constant amount of time so that an ionic strength of the detector recovers by the termination of the suspension period.