Patent ID: 8445844

Claim:
A quadrupole mass spectrometer including an ion source for ionizing sample molecules, a quadrupole mass filter for selectively allowing passage of an ion having a specific mass-to-charge ratio among ions produced by the ion source, an ion optical system located between the ion source and the quadrupole mass filter in order to transport the ions produced by the ion source to the quadrupole mass filter, and a detector for detecting an ion that has passed through the quadrupole mass filter, comprising: a) a voltage-applying ion-drawing section for applying a DC bias voltage to the quadrupole mass filter in order to create a DC electric field for drawing the ions into the quadrupole mass filter, the DC electric field being created between the quadrupole mass filter and the ion optical system; b) a memory section for storing beforehand bias voltage information utilized in the ion-drawing section, the bias-voltage information including a plurality of scan speeds and, for each scan speed, a specific mass-to-charge ratio and a specific DC bias voltage; and c) an analysis-performing section for performing an analysis of a target sample under a condition that the scan speed has been specified as one of analysis conditions, while controlling the voltage-applying ion-drawing section on a basis of the bias voltage information stored in the memory section so that the DC bias voltage changes according to the specified scan speed and in response to a change in the mass-to-charge ratio due to a mass-scanning operation.