Mass spectrometer

A mass spectrometer provided with a high-voltage power source for applying a high voltage to a specific section in order to perform an ionization and mass spectrometry of a component in a sample, the mass spectrometer characterized in that:

• the high-voltage power source comprises:
• a positive voltage generation section for generating a high positive voltage;
• a negative voltage generation section for generating a high negative voltage;
• a voltage control section for operating each of the positive and negative voltage generation sections so that a predetermined voltage is generated in each voltage generation section;
• and a charge release assistant section to which a pair of positive output terminals of the positive voltage generation section and a pair of negative output terminals of the negative voltage generation section are connected, where the charge release assistant section is configured as follows:
• in a switching operation between a positive voltage output and a negative voltage output under a command of the voltage control section, when the voltage between either the positive output terminals or the negative output terminals is equal to or higher than a predetermined level, the charge release assistant section reduces an impedance between the other pair of output terminals having an opposite polarity so as to release electric charges accumulated at these output terminals immediately before the impedance is reduced;
• and
• the mass spectrometer comprises a controller for controlling the voltage control section as follows:
• when an output voltage supplied from the high-voltage power source is changed from |V1| to |V2| (where |V1|>|V2|) without changing a polarity of the output voltage, the positive voltage generation section and the negative voltage generation section are operated so as to temporarily switch the polarity of the output voltage for a predetermined period of time from a state where the positive voltage generation section and the negative voltage generation section are being operated so as to maintain the output voltage at |V1|, and subsequently, the positive voltage generation section and the negative voltage generation section are operated so as to switch the polarity of the output voltage back to the polarity used before the temporary switching operation and settle the output voltage at |V2|.