Stable Isotope Standards
Deuterated internal standards and stable isotope-labelled reference materials
Deuterium and carbon-13 labelled internal standards for isotope-dilution LC-MS/MS quantitation, recovery assessment and bioanalytical method validation.
How deuterated internal standard are characterised and released
A stable isotope-labelled internal standard co-elutes with the analyte and experiences the same extraction losses and ionisation suppression, which is why isotope dilution remains the most reliable way to quantify a small molecule by LC-MS/MS in a complex matrix.
Selection comes down to three properties: sufficient mass difference to avoid isotopic overlap with the unlabelled analyte, isotopic enrichment high enough that the unlabelled contribution is negligible, and label placement on a position that will not exchange under the sample preparation conditions.
Each labelled standard here reports isotopic enrichment and chromatographic purity on the lot Certificate of Analysis, so the unlabelled contribution can be accounted for in the calibration model.
Released standards in this category
3 materials
| Caffeine-13C3 Stable Isotope Standard | 78072-66-9 | 13C3C5H10N4O2 | ≥ 99.0% | $132.00 |
| Ibuprofen-d3 Stable Isotope Standard | 1189460-56-9 | C13H15D3O2 | ≥ 99.1% | $118.00 |
| Paracetamol-d4 Stable Isotope Standard | 64315-36-2 | C8H5D4NO2 | ≥ 99.2% | $108.00 |
Frequently asked
- What isotopic enrichment is supplied?
- Deuterated materials are supplied at ≥ 98 atom % D and carbon-13 materials at ≥ 99 atom % 13C. The determined value for the shipped lot is stated on the Certificate of Analysis.
- How much mass difference is needed?
- A separation of at least three mass units from the unlabelled analyte is generally preferred so that the natural isotopic envelope of the analyte does not contribute to the internal standard channel.
- Will the deuterium label exchange during sample preparation?
- Labels are placed on non-exchangeable positions wherever the synthesis allows. The label position is stated in the product synonyms so exchange risk can be assessed against your extraction chemistry.