Analysis of Water ¹⁸O and H/D by Laser-Absorption Spectroscopy

The SIF provides simultaneous analysis of ¹⁸O/¹⁶O and D/H isotope ratios in liquid water samples using an LGR DLT-100 (Los Gatos Research, Inc., Mountain View, CA, USA). Samples (0.75 µL) are injected 6 times each, the first 3 injections are discarded to avoid ‘memory,’ the average of injections 4-6 is used for isotope ratio calculations. Working standard waters calibrated against NIST standard reference materials (VSMOW, GISP, SLAP), are inserted in the sample sequence (usually before and after each group of 6 unknowns). Sample isotope ratios are adjusted to working reference waters. Precision is normally <0.8 per mille for DH and <0.3 per mille for ¹⁸O.

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 conical bottom vials for low-volume samples. Minimum volume is 50 µL; preferred volume is 1 mL. Please do not fill vials more than half full. 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.

Analysis Order Form

Please include an Analysis Order Form with any samples you deliver to the Stable Isotope Facility. 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 recommend completing a separate form for each type of analysis.

Shipping and contact information:
David Harris
UC Davis Stable Isotope Facility
Department of Plant Sciences
One Shields Avenue, Mail Stop 1
Davis, CA 95616
USA

Phone:(530) 754-7517, Fax: (530) 752-4361
E-mail: dharris@ucdavis.edu

Supplies

Tips

1)Do not fill vials more than half full.

2)Avoid over-tightening caps