Introduction The time-of-flight mass spectrometer (TOFMS) is one of mass spectrometry techniques, which include the quadrupole mass spectrometer, the magnetic sector mass spectrometer, the ion trap mass spectrometer and the Fourier transform ion cyclotron resonance mass spectrometer. In the case of TOFMS, ions of various m/z values, which are generated in the ion source, are accelerated to the detection plane by a pulse voltage applied from a starting time of data acqisition. Since the time-of-flight of ions at the detection plane are proportional to the square root of their m/z values, the ions generated in the ion source can be separated. One of the TOFMS feature is fast measurement, which is due to the unnecesity of scan for any physical parameters such as electric or magnetic fields. Recently, not only a single type mass spectrometer, but also a tandem type mass spectrometer connected with the quadrupole mass spectrometer (Q/TOF) or tandemly connected two TOFMSs (TOF/TOF) are available.