isotopic carrier

https://doi.org/10.1351/goldbook.I03340
A carrier which differs only in isotopic composition from the trace it has to carry.
Source:
PAC, 1994, 66, 2513. 'Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994)' on page 2516 (https://doi.org/10.1351/pac199466122513)