Selective ultra trace isotope determination in environmental and bio-medical studies by high-resolution resonance ionization mass spectrometry

摘要

The precise determination of relative abundances of ultra trace isotopes in the range below 10~(-9) is of importance for a wide spectrum of applications in fields like environmental protection, cosmo-chemistry, bio-medical tracer studies or geological and geo-chronological investigations. The necessary high isotopic selectivity, rather complete isobaric suppression and good overall efficiency for these investigations is provided by high-resolution resonance ionization mass spectrometry. Multi-step continuous wave laser excitation and ionization using diode lasers at a compact quadrupole mass spectrometer has been optimized to become a powerful and reliable experimental method, which is just becoming competitive to accelerator mass spectrometry. With this technique we have performed measurements with high isotopic selectivity above 10~(10) on the isotopes ~(90)Sr and ~(41)Ca while further studies concern Gd and Pu isotopes. In all cases extensive atomic spectroscopic investigations were required as basis for analytical studies.