isotopic tracer

https://doi.org/10.1351/goldbook.I03350
A tracer which only differs in isotopic composition from the substance to be traced.
Source:
PAC, 1994, 66, 2513. 'Nomenclature for radioanalytical chemistry (IUPAC Recommendations 1994)' on page 2526 (https://doi.org/10.1351/pac199466122513)