Term: selectively labelled
https://doi.org/10.1351/goldbook.S05556

Definition:
An isotopically labelled compound is designated as selectively labelled when a mixture of isotopically substituted compounds is formally added to the analogous isotopically unmodified compound in such a way that the position(s) but not necessarily the number of each labelling nuclide is defined. A selectively labelled compound may be considered as a mixture of specifically labelled compounds.

Related Terms:
1) isotopically labelled (http://doi.org/10.1351/goldbook.I03336).
2) isotopically substituted (http://doi.org/10.1351/goldbook.I03338).
3) isotopically unmodified (http://doi.org/10.1351/goldbook.I03339).
4) specifically labelled (http://doi.org/10.1351/goldbook.S05793).
5) labelling (http://doi.org/10.1351/goldbook.L03425).
6) nuclide (http://doi.org/10.1351/goldbook.N04257).

Source: Blue Book, p. 515 (https://www.acdlabs.com/iupac/nomenclature/)

Citation: 'selectively labelled' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.S05556

License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms.

Disclaimer: The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.