Deuterated and Stable-Isotope-Labelled Compounds chemicals

What these compounds are

Stable-isotope-labelled compounds have one or more atoms replaced by a heavier, non-radioactive isotope: deuterium for hydrogen, carbon-13 for carbon-12 or nitrogen-15 for nitrogen-14. The labelled molecule behaves almost exactly like the original in extraction and chromatography but has a different mass, which a mass spectrometer separates easily. Deuterated solvents such as chloroform-d and DMSO-d6 are also standard in NMR.

Key specification points

• Chemical purity by HPLC, typically 95 to 98 percent or more.
• Isotopic enrichment, usually 98 to 99 atom percent at the labelled positions.
• Unlabelled content, ideally 0.1 to 0.5 percent or less, so it does not bias results.
• Identity and label position confirmed by NMR and MS.

When to choose them

Use labelled internal standards for quantitative LC-MS/MS bioanalysis, nitrosamine and trace impurity methods, environmental residues and metabolic tracing. A mass shift of at least 3 Da is usually preferred, and labels on exchangeable positions should be avoided.

Documentation

Each compound ships with a COA giving chemical purity and isotopic enrichment, with NMR and MS data. See Impurity Reference Standards.