Combining Isotope Dilution and Standard Addition-Elemental Analysis in Complex Samples.

A new method combining isotope dilution mass spectrometry (IDMS) and standard addition has been developed to determine the mass fractions of different elements in complex matrices: (a) silicon in aqueous tetramethylammonium hydroxide (TMAH), (b) sulfur in biodiesel fuel, and (c) iron bound to transferrin in human serum. All measurements were carried out using inductively coupled plasma mass spectrometry (ICP-MS). The method requires the gravimetric preparation of several blends (b)-each consisting of roughly the same masses () of the sample solution (x) and of a spike solution (y) plus different masses () of a reference solution (z).