Water - δD, δ18O
We employ two Picarro liquid water laser analyzers dedicated to measuring δD and δ18O of water. We are tied to the VSMOW international scale via VSMOW and SLAP for our water isotope measurements. We maintain a suite of in-house reference waters measured against VSMOW and SLAP using GISP as a quality standard.
If you would like to submit water samples for δD and δ18O analysis, we prefer a minimum of 5 mL of sample in a labeled water tight plastic or glass container. Simple legible sample IDs are appreciated. We need to know if it is fresh or salt water. Analysis costs are here.
300 uL vials are loaded with 200 uL of sample or reference water and placed in a PAL autosampler tray. The δD and δ18O are measured 6-10 times for each vial from 1 µL of water per injection. Between each injection, the cavity is purged with dry air and partially evacuated with a small pump.
Our nominal long-term external precision is less than 0.1 permil (1 σ) for δ18O and less than 1 permil (1 σ) for δD.
Standard Operating Procedures
- Gupta P, Noone D, Galewsky J, Sweeney C, Vaughn BH. (2009) Demonstration of high-precision continuous measurements of water vapor isotopologues in laboratory and remote field deployments using wavelength-scanned cavity ring-down spectroscopy (WS-CRDS) technology. Rapid Communications in Mass Spectrometry 23. doi: 10.1002/rcm.4100
- O'Keefe A, Deacon DAG. (1988) Cavity ringdown optical spectrometer for absorption measurements using pulsed laser sources. Review of Scientific Instruments 59. doi: 10.1063/1.1139895
- Zalicki P, Zare RN. (1995) Cavity ringdown spectroscopy for quantitative absorption measurements. Journal of Chemical Physics 102. doi: 10.1063/1.468647