Measurement equations for the determination of the Si molar mass by isotope dilution mass spectrometry

A new method applying isotope dilution mass spectrometry to determine the molar mass of a silicon sample, highly enriched with respect to 28 Si, has been proposed recently. This paper describes a different way of calculating the molar mass by solving an equation linking the measurement results to the ratio between the amount-of-substance fractions of 28 Si and 30 Si in the sample. The mathematical model and the final measurement equation are much more straightforward than those previously reported, though fully equivalent.