Laser Tandem Mass Spectrometry in a Time of Flight Instrument

We present a new laser tandem mass spectrometry technique in a reflectron time of flight (TOF) instrument. A first pulsed laser performs the multiphoton ionization and the primary photodissociation. A newly designed ion source permits a high mass resolution in the space focus of the 12 cm long first linear TOF, where then the secondary excitation can take place. For high resolution applications the pure secondary or pure metastable mass spectrum of a preselected precursor ion can be recorded using a new reflectron scanning technique. It is also possible to obtain the whole secondary mass spectrum with one cycle using a new postacceleration method. Several techniques for ejection of interfering ions are shown. The features of our techniques are demonstrated at various primary fragments of benzene.