Patent ID: 6573496
Filing Date: 2003-06-03
Classification: H01J

Abstract:
A quadrupole mass spectrometer, comprising:an ion source for ionizing a sample molecule, a quadrupole filter situated near the ion source for selectively passing ions among ions generated in the ion source, a detector situated near the quadrupole filter for detecting the ions having passed through the quadrupole filter, and a control device connected at least to one of the ion source and the quadrupole filter, said control device, when a voltage to be applied to the quadrupole filter is scanned to successively change a mass number of the ions passing through said quadrupole filter, temporarily changing a DC-type electric field of at least a part of a space between the ion source and the quadrupole filter according to a timing of passage of ions with a specific mass number set in advance through the quadrupole filter to thereby prevent the passage of the ions with the specific mass number.