Ja. Pfander et al., Determination of Y, Zr and ultra-low Nb concentrations in geological material by multi-ion counting spark-source mass spectrometry (MIC-SSMS), FRESEN J AN, 364(5), 1999, pp. 376-380
Precise concentrations of Zr, Y and Nb in the mu g/g to ng/g range have bee
n determined in rock samples using multi-ion counting spark-source mass spe
ctrometry (MIC-SSMS). A high resolution method, combined with interference
correction on Zr-91 and Nb-93 for low concentration samples, was applied. A
n analytical precision of 2-5% for concentrations down to 0.020 mu g/g and
10% for lower concentrations was attained. The detection limit is below 0.0
05 mu g/g.. By measuring international reference materials, the accuracy of
the method was determined to be within about 10% of the recommended values
. However, the accuracy of the final concentration is influenced by interfe
rence corrections, but the additional error is below 20%. The interference
problem is most difficult for Al-rich samples (>15% Al2O3), as the interfer
ing molecules an (CaAlC2+)-Ca-40-Al-27-C-12 and (Al3C+)-Al-27-C-12. The acc
ordance between ICP-MS and MIC-SSMS results is worse for low Nb concentrati
ons in the ng/g range. Here, ICP-MS gives systematically lower values than
MIC-SSMS. The reason for this discrepancy is not yet clear, but may be caus
ed by Nb loss during chemical treatment of the samples prior to ICP-MS meas
urements.