substoichiometric isotope dilution analysis
A kind of isotope dilution analysis in which the final isotopic abundance is estimated from the amount of the nuclide present in a known quantity of the relevant element separated from the test portion, where this quantity is smaller than the total amount of that element present in the test portion.
PAC, 1994, 66, 2513. 'Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994)' on page 2521 (