Isotopically Labeled and Unlabeled Reference Standards


Custom Synthesis Services

Submit a Sample for Chemical Analysis

Our core business is in the small-scale (milligram to gram) synthesis of pharmaceutical active organic compounds for research purposes and use as Certified Analytical Reference Standards. If you can draw it, we can probably synthesize it (at a price of course, that covers our R&D efforts!).

Stable Isotope Labeled (SIL) and Unlabeled Reference Standards

We specialize in small-scale synthesis of:

- APIs
- Metabolites
- Impurities
- Analogues
- Intermediates

With decades of combined experience, we are experts in the synthesis of stable labeled APIs and metabolites. Our extensive experience allows us to place deuteriums in the most stable positions to limit exchange, which ensures the quality of your assay. In cases where deuterium labeling is not desirable, we happily rely on 13C or 15N.

We are a registered DEA lab for Schedules I to V controlled compounds.


We have a large number of Anaytical Reference Standards available in stock for delivery. Please view our catalog of high-purity compounds and sealed solutions or request a quote for those listed and for custom-synthesis of those that are not listed in our catalog.


Full-time Equivalent (FTE) service is also available for R&D efforts, custom-synthesis of comounds with limited or no literature precedent requiring synthesis method development, or for primarily research oriented projects.


Quality Matters

Are you buying poorly characterized and unsupported reference standards? You don't need to settle for TLC or single wavelength purity determination.

With our full chemical certification, you will never need to doubt the authenticity or purity of Chemtos reference standards. Every compound provided by Chemtos comes fully certified with UV Diode Array HPLC purity analysis, proton NMR analysis, LC/MS and all of the supporting data. All analytical work is done under GLP conditions. Concentrations of our single use reference standard solutions in fame sealed ampules are verified by Quantitative proton NMR in order to independently confirm the stated potency/concentration value. See a sample Certificate of Analysis.

Learn more about the Chemtos Difference