Multiple-ion-beam time-of-flight mass spectrometer

An innovative approach to increase the throughput of mass spectrometric ana lyses using a multiple-ion-beam mass spectrometer is described. Two sample spots were applied onto a laser desorption/ionization target and each spot was simultaneously irradiated by a beam of quadrupled Nd:YLF laser radiatio n (261.75 nm) to produce ions by laser-desorption ionization. Acceleration of the ions in an electric field created parallel ion beams that were focus ed by two parallel einzel lens systems. After a flight path of 2.34 m, the ions were detected with a microchannel plate-phosphor screen assembly coupl ed with a charge coupled device camera that showed two resolved ion beams. Time-of-flight mass spectra were also obtained with this detector. Experime nts were performed using both metal atom cations (Ti+ and Cr+) produced by laser desorption/ionization and the molecular ions of two different protein s (myoglobin and lysozyme), created by matrix assisted laser desorption/ion ization using an excess of nicotinic acid as matrix. (C) 2001 American Inst itute of Physics.