Abstract: A gas chromatograph mass spectrometer includes a gas chromatograph part including a separation column, a mass spectrometer part, and a controller configured to control at least an ionization part of the mass spectrometer part. The ionization part includes an ion source box having a space for ionizing the components flowing out from an outlet of the separation column in the inside, a heater for adjusting a temperature of an ion source box, and a filament that is arranged outside of the ion source box and generates an electron for ionizing the components flowing out from the outlet of the separation column. The controller is configured to, after applying voltage to the filament, adjust a temperature of the ion source box affected by heat emitted from the filament to a predetermined temperature by controlling output of the heater in relation to magnitude of heat generation of the filament.

Abstract: All data obtained from an A/D converter during a summation period with values exceeding a prescribed threshold is excluded from summation up to a prescribed maximum number of deletions, and the values of the remaining data are summed to find one piece of measurement data corresponding to that summation period. The number of pieces of noise data reflecting the influx of particles that cause spike-like noise is extremely small, so noise data is removed in a state in which there are no signals and no target ions are present. When target ions are present, legitimate data which is not noise data may be removed, but the number of pieces of removed data is small in comparison to the total number of pieces of data, so the effects of the removal of legitimate data essentially do not emerge in the summation results. It is therefore possible to effectively reduce spike-like noise.

Abstract: The quadrupole mass spectrometer according to the present invention includes an ion source; a quadrupole filter including four rod electrodes for allowing ions having a preset mass number (mass/charge) among those ions generated by the ion source to pass through the space surrounded by the four rod electrodes; an ion detector for detecting the ions passing through the space; a quadrupole driver for applying a DC+RF voltage to the four rod electrodes, where the voltage corresponds to the preset mass number; a scanning controller for changing the voltage applied to the four rod electrodes to scan through a preset scanning range of the mass number; and a field controller for producing an electrical field between the ion source and the quadrupole filter, where the magnitude of the electrical field depends on the scanning speed of the scanning controller.

Abstract: In a quadrupole mass spectrometer, a controlling portion controls a lens power source to temporarily change a voltage applied to an ion lens according to a timing for controlling a quadrupole power source, so that excessive ions do not pass through a quadrupole filter. Therefore, the excessive ions are diffused on the way to thereby prevent the excessive ions from reaching a detector. Thus, at the time of operation, a large quantity of ions, such as carrier gas molecular ions, unnecessary for the analysis is prevented from being introduced into the detector to deteriorate thereof.

Abstract: The quadrupole mass spectrometer according to the present invention includes an ion source; a quadrupole filter including four rod electrodes for allowing ions having a preset mass number (mass/charge) among those ions generated by the ion source to pass through the space surrounded by the four rod electrodes; an ion detector for detecting the ions passing through the space; a quadrupole driver for applying a DC+RF voltage to the four rod electrodes, where the voltage corresponds to the preset mass number; a scanning controller for changing the voltage applied to the four rod electrodes to scan through a preset scanning range of the mass number; and a field controller for producing an electrical field between the ion source and the quadrupole filter, where the magnitude of the electrical field depends on the scanning speed of the scanning controller.

Abstract: In a quadrupole mass spectrometer, a controlling portion controls a lens power source to temporarily change a voltage applied to an ion lens according to a timing for controlling a quadrupole power source, so that excessive ions do not pass through a quadrupole filter. Therefore, the excessive ions are diffused on the way to thereby prevent the excessive ions from reaching a detector. Thus, at the time of operation, a large quantity of ions, such as carrier gas molecular ions, unnecessary for the analysis is prevented from being introduced into the detector to deteriorate thereof.