ISOTOPE SELECTIVE ELEMENT ANALYSIS BY DIODE-LASER ATOMIC-ABSORPTION SPECTROMETRY

The analytical figures of merit of isotope selective diode laser atomi c absorption spectrometry (DLAAS) in low-pressure graphite furnaces ar e given for lithium and rubidium. While Li-6 and Li-7 were measured by Doppler-limited as well as by Doppler-free absorption spectroscopy of the 670.79nm resonance line, Doppler-free saturation spectroscopy was applied for analysis of the Rb-85 and Rb-87 D2 resonance line at 780. 03 nm. Three different modulation techniques were applied and compared : (i) intensity modulation, (ii) wavelength modulation, and (iii) a co mbination of intensity and wavelength modulation.