Patent ID: 9269551
Filing Date: 2016-02-23
CPC Classification: G01N,H01J

Claim Text:
1. A tandem quadrupole mass spectrometer comprising: a front-stage quadrupole mass filter for selecting, as precursor ions, ions having a specific mass-to-charge-ratio from among a variety of ions; a collision cell for causing the precursor ions to collide with a predetermined gas to dissociate the ions; a rear-stage quadrupole mass filter for selecting ions having a specific mass-to-charge-ratio from among a variety of product ions produced through the dissociation; and a detector for detecting the selected product ions, the tandem quadrupole mass spectrometer further comprising: a) a gas adjuster for adjusting a supply pressure or a supply flow rate of a gas supplied to an inside of the collision cell such that a gas pressure inside the collision cell is in a desired state; and b) a controller for changing a length of a dwell time in accordance with the gas supply pressure or the gas supply flow rate set by the gas adjuster or a target gas pressure when a measurement in a multiple reaction monitoring measurement mode is performed, the dwell time being a period of time to take in signals obtained by the detector with regard to precursor ions and product ions originating from one compound.