Sample Preparation


Sample Submission

UC Davis Plant Sciences

Carbon Dioxide (CO2) Analysis by Trace Gas-IRMS Tips

Example of a puckered septa1) Avoid over-tightening vial caps. Vials will leak when caps are over-tightened, causing the septa to pucker and pull away from the vial. Turn caps until snug, but not so far that the septa start to pucker.
2) Do not apply silicone grease, adhesives, or sealant to the tops of the vials. These materials clog the autosampler needle. The process of removing these sealants increases the risk of losing your gas sample due to dislodged septum. The SIF may decline your order and return the samples, plus shipping cost.

3) Always use new septa; dry, cracked, or repeatedly pierced septa may leak.

4) Avoid excessive labels and tape, because the vials will be too wide to fit in our autosampler rack.

5) Gas vials should be free of particulate matter or slurries, as the particles will clog our autosampler needle.


Carefully package small groups of Exetainers in Ziplock bags, small boxes, or in their original boxes with dividers. Then package these sets in a larger, sturdy box with Styrofoam peanuts or bubble wrap. Make sure the samples are very secure, loose vials can shatter during shipping. We generally do not return vials or shipping containers.

Please complete and submit the online Analysis Order Form and Sample List for your samples.  Also, be sure to include a printed copy with your samples. The SIF uses this form to track your samples and to contact you regarding receipt of samples, data, and invoicing. For mixed analysis requests, we require a separate form for each type of analysis.

e-mail: | phone: 530-752-8100 | fax: 530-752-4361
UC Davis Stable Isotope Facility | Department of Plant Sciences
One Shields Avenue | Davis, California, 95616 | USA