Since 2000, our laboratory and collaborators have provided organic reference materials for stable isotope analyses for the global research community. We sincerely thank our supporters and would like to hear from you if you have questions or suggestions with regard to existing or potential future reference materials. Feedback from endusers helps us maintaining high quality service. Email to: arndtschimme@gmail.com.
You can see additional descriptions of, and technical advice about the reference materials by clicking on the Guidance for Types of Organic Reference Materials tab in the side navigation, and from there to specific categories.
Note: Stable isotope ratios of individual compounds may be subject to slight adjustments over time. For example, the development of new materials routinely employs repeat measurements of older materials together with calibrations using pairs of international standards for anchoring and attenuation of isotopic scales, thus occasionally resulting in amended statistical mean δ-values of older reference materials.
Hydrocarbon gases like methane are sealed at atmospheric pressure in 9-mm o.d. glass tubes with a break-seal. The internal volume of ca. 10 milliliter facilitates shipping as non-hazardous reference material. The upper image shows sealed glass tubes, whereas the lower image magnifies one sealed long "break seal" neck and three unsealed top parts of ampoules.
Many liquid reference materials are sealed under argon in glass ampoules.
Most solid n-alkanes are sealed in amounts of no less than 5 milligram in glass capillaries.
The USGS67, USGS68, and USGS69 hexadecanes are sealed in amounts of 50 microliter in long glass capillaries. For details, see: Schimmelmann et al., 2016, Analytical Chemistry 88 (8), 4294-4302. https://doi.org/10.1021/acs.analchem.5b04392
Longer-chain n-alkanes are either filled as wax particles into glass vials, or are shipped as wax droplets at the end of short glass rods inside glass vials.
An n-alkane wax droplet with a weight of more than 5 milligram adheres to the end of a glass rod inside a crimp-sealed glass vial.
USGS77 (polyethylene powder) is available in glass vials. Oils USGS78 and NBS 22a are sealed under argon in glass ampoules. For details, see: Schimmelmann et al., 2016, Analytical Chemistry 88 (8), 4294-4302. https://doi.org/10.1021/acs.analchem.5b04392
Many solid organic USGS reference materials are available in crimp-sealed glass vials. For example, see: Schimmelmann et al., 2016, Analytical Chemistry 88 (8), 4294-4302. https://doi.org/10.1021/acs.analchem.5b04392
6 different types of ethanols from C3 (e.g., potato) and C4 (e.g., sugar cane) origins are available as 5-milliliter aliquots sealed under argon in glass ampoules, encompassing different ethanol concentrations in water, all the way to pure 200-proof ethanols.