Sample Weight Calculator - Carbon and Nitrogen in Solids

The Stable Isotope Facility (SIF) will be closing, effective July 26, 2026.

June 3, 2026
An Update on the Plant Sciences Stable Isotope Facility

Dear Faculty, Staff, Students, and Supporters,
After a lengthy review process and careful consideration, we have made the difficult decision to sunset the Stable Isotope Facility (SIF) in its current form, effective July 26, 2026.

The Department of Plant Sciences continues to face hard decisions surrounding funding allocation given the campus-wide request to reduce budgets. Over the past several years SIF has been operating with a significant and growing deficit and, despite extensive efforts over the last several months to find a solution that would allow the facility to continue to provide services to the research community, we have not found a model that is financially sustainable.

I want to thank SIF’s staff for their excellent work and dedication these past 25 years, and everyone who has played a role in supporting this facility.

We are committed to doing our best to support the researchers who rely on the facility during this transition, and will be in touch with individual clients about details of specific plans for handling existing orders over the next several weeks.

Sincerely,
Daniel Potter
Professor and Chair, Department of Plant Sciences
University of California, Davis

Original Letter

UC Davis Stable Isotope Facility - Sample Weight Calculator
 

Instructions:

To calculate your optimal sample weights, enter %N and %C values for your sample material in the blue cells. Calculated results are shown in the green cells. See table for examples of %N and %C values for various materials. Samples must not exceed either 75mg total weight or 12mg of carbon. Enriched sample weights should be optimized for 20 ug N, with a maximum of 100 ug N (i.e. use the "Smallest sample weight" to "Optimal sample weight" as your target range). Contact the Stable Isotope Facility if you don't have the minimum amount of material required.

Please send feedback or questions to [email protected].