CBNM certification of rubidium in human serum reference material by isotope dilution mass spectrometry
Isotope Dilution Mass Spectrometry (IDMS) was applied for the determination of rubidium in biological fluids. Analyses of blood, blood serum and plasma with a rubidium concentration in the order of magnitude 2 microg/g blood resp. 0.2 microg/g serum or plasma were carried out with a total uncertainty smaller than 1% (2s). As an example of the potential of the method, the analysis of a reference material is shown. Ten aliquots of a freeze-dried human serum reference material were sampled gravimetrically and were spiked with an enriched 87Rb-Isotopic Reference Material (CBNM-IRM 618) with a certified 87Rb concentration. Rubidium was purified by cation-exchange. 85Rb/85Rb isotope abundance ratio measurements were performed by solid sample positive thermal ionisation mass spectrometry, using two instruments. There is no difference in the propagated overall uncertainty on the concentrations determined with both instruments. The homogeneity of the reference material, with respect to the Rb content, as determined on ten aliquots is within 3%. The high precision of IDMS allows the detection of slight differences in the rubidium concentration of the ten individual aliquots, raising the question about inhomogeneities at the 2% level.
Bibliographic Reference: Paper presented: 12th International Mass Spectrometry Conference, Amsterdam (NL), Aug. 26-30, 1991
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Record Number: 199111348 / Last updated on: 1994-12-02
Original language: en
Available languages: en