Development of JMS-S3000: MALDI-TOF/TOF Utilizing a Spiral Ion Trajectory
We have developed the JMS-S3000, matrix assisted laser/desorption ionization time-of-flight mass spectrometer (MALDI-TOFMS). An innovative ion optical system, which achieved a spiral ion trajectory, surpassed basic specification of the reflectron ion optical system presently used in most commercially available TOFMSs. Furthermore, we have developed the TOF-TOF option for the JMS-S3000. In the case of attaching the TOF-TOF option, a spiral ion optical system is adopted for the first TOFMS, whereas a reflectron ion optical system with offset parabolic reflectron is adopted for the second one. Utilizing the spiral trajectory ion optical system, the JMS-S3000 provides unprecedentedly high mass resolution and high precursor ion selectivity. In this paper, we demonstrate not only the high mass resolution of more than 60,000 (FWHM) at m/z 2093 but also achievement of high mass resolution over a wide mass range. In addition, we present the high selectivity that enables selection of monoisotopic ions of precursor ions. By selecting only monoisotopic ions of precursor ions, one signal peak corresponding to each fragmentation channel is observed on a product ion spectrum. Consequently, the analysis of the product ion spectrum is made clearer.
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.