Current developments and principles of laser-based resonance ionization mass spectrometry

Resonance ionization mass spectrometry (RIMS), a promising technique mainly devoted (although not limited) to ultratrace chemical analysis, is discussed. In RIMS systems, suitable tunable lasers stepwise bring each atom to ionization and assure at the same time the saturation of the spectroscopic transitions involved. Therefore, in a given complex sample single-atom detection of the analyte is virtually achievable. In the authors' system, atomization is achieved by thermal heating and/or ion bombardment. Three excimer-pumped tunable dye lasers allow selectivity of a large number of atomic elements; selectivity is inherently related to sensitivity. The use of a high-throughput, linear, time-of-flight mass filter improves SNR and permits parallel isotopic analysis in cases of sufficiently large and uniform laser spectral bandwidth. The electronic signal acquisition and processing, a potential bottleneck in the apparatus, is based on CAMAC instrumentation.