Stable Isotope Facility

Oxygen (¹⁸O) and Hydrogen (D/H) Water Sample Preparation and Organization

The standard volume for water samples is 1-1.4mL. Contact the SIF about low volume samples (<500µL). 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. Samples should be kept refrigerated and in the dark. Additional preservation is not necessary. We do not accept samples preserved with mercuric chloride (HgCl₂). Samples will be stored for 3 months after you have received your data.

Supplies
Submit samples in standard autosampler vials (volume: 2 mL, 12 mm O.D. x 32 mm length) with screw caps (regular 9-425 or wide-mouth 10-425). Samples not submitted in autosampler vials will be charged a transfer fee (see Pricing). For low-volume samples (less than 250 µL), use the appropriate polypropylene insert molded vials (C4013-11 and C4013-60A, see below).

The following is a list of the vials we use. Other suitable vials are available from a variety of suppliers. We suggest screw-top vials with write-on labels. Both regular (8 mm) and wide-mouth (10 mm) closures are acceptable.

Manufacturer / Part#	Description
National Scientific / C4010-1W	Vials, 2 mL, 10 mm screw thread, clear glass, write-on patch
National Scientific / C4010-40A	Screw caps with septa, 10 mm (PTFE/Silicone/PTFE)
Microliter Analytical Supplies Inc. / 09-1400	Conical bottom vials, 1.8 mL, 8 mm screw thread, clear glass (for samples < 300 µL)
Microliter Analytical Supplies Inc. / 09-0040	Screw caps with septa, 8 mm (PTFE/Silicone/PTFE)
National Scientific / C4013-11	250 µL, polypropylene, 12x32mm, conical, 8-425 screw thread vial (for samples < 100 µL)
National Scientific / C4013-60A	Screw caps with septa, for 8-425 vials, (PTFE/Silicone)
National Scientific / C4012-25	Storage rack for 50 vials, polypropylene, without lid
National Scientific / C4011-25	Storage rack for 100 vials, polystyrene, with lid

Organizing samples
In order to use the correct reference waters, please group water samples into the following classes:

Group	dD/H	d18O
Natural Abundance	Up to 60 permil	Up to 6 permil
Low Enrichment	60 to 12000 permil (0.5 at-%)	6 to 1500 permil (0.2 at%)
High Enrichment	Over 12000 permil (>0.5 at-%) not accepted	Over 1500 permil (>0.2 at%) not accepted

For tracer studies, estimates on isotope values are required and samples must be organized by increasing concentration.

Saline samples must be clearly marked with an estimate of the salinity. Organize saline samples in order of increasing salinity.

Turbid water samples or water samples containing precipitate must be filtered prior to analysis. If SIF determines a water sample requires filtering, a $5.00 fee will be charged per sample for this service.

Contact UC Davis SIF concerning the analysis of acidic or basic solutions. These solutions must be neutralized before processing.

Shipping
Carefully package racks of vials in ziplock bags, small boxes, or their original boxes. 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 break during shipping. Please ship with a refrigerant of some sort (dry ice, blue ice, etc.). Coolers will not be returned.

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 the completion of a separate form for each type of analysis.