Patent ID: 8803086

Claim:
A triple quadrupole mass spectrometer including: an ion source for ionizing sample components; a front-stage quadrupole mass filter for selecting, as a precursor ion, an ion having a specific mass-to-charge ratio from among various ions produced by the ion source; a collision cell for dissociating the precursor ion by making the precursor ion collide with a predetermined gas, the collision cell containing an ion guide for transporting ions while focusing the ions by a radio-frequency electric field; a rear-stage quadrupole mass filter for selecting an ion having a specific mass-to-charge ratio from among various product ions produced by dissociation of the precursor ion; and a detector for detecting the product ion selected by the rear-stage quadrupole mass filter, wherein: the front-stage quadrupole mass filter, the ion guide, and the rear-stage quadrupole mass filter are arranged so that a straight ion-beam axis in the front-stage quadrupole mass filter and a straight ion-beam axis in the ion guide obliquely intersect with each other, forming an inflected line in a space between the front-stage quadrupole mass filter and the collision cell, while the straight ion-beam axis in the ion guide and a straight ion-beam axis in the rear-stage quadrupole mass filter are in a form of a straight line; and a voltage supplier for applying a direct-current voltage to an ion lens provided at an entrance of the collision cell, so as to form a direct-current electric field by which an ion which has passed through the front-stage quadrupole mass filter is made to bend along the inflected ion-beam axis.