Compound-Specific Stable Isotope Analysis (CSIA)

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

n-Alkane Sample Preparation

Submit samples in standard GC vials (volume: 2 mL O.D. x length: 12 x 32 mm) with screw caps (9-425 or 10-425). Use inserts for low-concentration samples. With inserts, we can inject up to 5 µL from as little as 40 µL solvent. Use vials with a write-on patch or use clear tape and permanent marker to label vials. Do not wrap vials with opaque marking tape – this makes it difficult to view liquid level. Thick tape causes vials to stick in the autosampler tray.

Total concentration of n-alkanes in samples should range from 0.5 to 4 µg C/µL, for typical samples having 10-20 moderate-sized peaks. Lower total concentration (~0.5 µg C/µL) are acceptable for samples having ≤10 major peaks. Moderate to large n-alkane peaks are 50-200 ng C/uL and the smallest detectable peaks are ~1.5 ng C, on-column.