Sample Preparation


Sample Submission

UC Davis Plant Sciences

Tips for Dissolved Organic Carbon (DOC) in Water

1) Do not freeze water samples that are in glass I-Chem vials. The vials will break during freezing and your samples will be lost. 50 mL centrifuge tubes or other freezer-friendly bottles are preferred for freezing your water samples. Quick freezing and dry-ice may cause the containers to crack. Instead, chill your water in a refrigerator for the first 12-24 hours prior to moving them to freezing temperatures. This gentle freezing method will reduce cracked bottles due to ice expansion.
2) Do not send samples preserved with mercuric chloride (HgCl2) nor sodium azide (NaN3). We do not guarantee the safe return shipment of these samples.

3) We are not currently accepting saline samples above 20 PSU.  Please contact the SIF for updates on the method development.

4) For optimum results, provide accurate DOC concentration estimates. The DOC system can analyze samples between 1.25 – 50 ppm DOC. Inaccurate or missing concentration estimates may delay your results.


Shipping Tips

Carefully package small groups of vials in ziplock bags, small boxes, or their original boxes with dividers to prevent impact. Then package these sets in a larger sturdy box with styrofoam peanuts or bubble wrap. Make sure the samples are well cushioned on all sides; loose bottles can break during shipping. Coolers will not be returned.


Ship your water samples in hard-walled coolers or Styrofoam insulated shipping kits. Do not use foam-only coolers nor cardboard-only boxes for the exterior shipping container; these containers will disintegrate due to condensation and hard impacts when tossed by couriers. Keep the entire shipment in refrigeration until time to ship. Fill any remaining “air space” in the cooler with newspaper or other filler, this assists with insulating your samples, and protects your container(s) when the couriers toss your shipment. Ship your samples overnight or 1-day express to arrive at the SIF on a Tuesday – Thursday to avoid delays with refrigeration. Blue ice blocks, cold packs, or ice blankets should be used to extend refrigeration, but each block should be wrapped with bubble wrap, as the frozen blocks can damage glass vials in the event of impact.


Please note: Samples will be stored by SIF for 3 months post-analysis and then discarded. Please review your results during this 3-month window.

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