Multi-element Analysis of Geological Samples

For many decades, spark source mass spectrometry (SSMS) was the method of choice for survey analyses of quite different types of geological materials, especially for the sensitive multi-element 

4 Trace Analysis of Selected Elements in Geological Materials 

China) after digestion with aqua regia and using flow injection online solid phase extraction ICP-MS in order to minimize the isobaric interferences is discussed by Fang et al6i 

Precise and accurate measurements of ultralow Nb, , Zr and Hf concentrations and the chondritic Zr/Hf and Nb/Ta ratios by MC-ICP-MS (Isoprobe, Micromass) were examined by Weyer et al.64 For the development of the isotope dilution technique, enriched 180Ta, 94Zr and 180Hf isotopes were applied for quantitative Zr, and Hf determination, and the monoisotopic element Nb was measured relative to Zr after quantitative separation from the matrix by ion exchange. 

Selected applications of inorganic mass spectrometry in trace analysis of geological samples are summarized in Table 9.34.3 8 9 52 

---

The laser beam efficiently vaporizes conductors, insulators, and semiconducting materials with a minimum of matrix effects. Laser sampling ICP-MS has also been applied successfully as a semi-quantitative survey tool for a rapid multi-element analysis of geological samples. The samples are pulverized to assure homogeneity. Some paraffin wax is mixed with the sample. The mixture is then placed in an aluminium cup and pressed into a wafer. 

K. P. Jochum, Trace element analysis of geological samples by modern spark source mass spectrometry using multi-ion counting, Spectrosc. Eur. 9, 22-27 (1997). 

In spite of the excellent capability and advantages (high selectivity and sensitivity) of RIMS for the ultratrace analysis of isotopes with naturally rare abundance in environmental, geological, medical and nuclear samples, no commercial instrumentation is available to date. In contrast to AMS and RIMS as mono-elemental (element-specific) analytical techniques, ICP-MS and LA-ICP-MS possess, in analogy to GDMS and SIMS, have the ability for multi-element analysis and thus could have the widest fields of application. 

For measurements of isotope ratios or isotope abundances, any of the mass spectrometers discussed in the previous chapters, such as SSMS, LIMS, GDMS56 and LA-ICP-MS,6 are of benefit for the direct isotope analysis of solid samples. SSMS and LIMS are rarely applied in isotope analysis due to their relatively low precision. Several applications of the isotope dilution technique as a calibration strategy in SSMS, mostly on geological samples, are known.57-59 GDMS has been mostly applied in multi-element trace analysis and depth profiling and plays only a minor role... 

---