Oxygen isotope measurements of seawater (H218O/H216O): A comparison of cavity ring-down spectroscopy (CRDS) and isotope ratio mass spectrometry (IRMS)
Laser-based spectroscopic techniques, such as cavity ring-down spectroscopy (CRDS), provide a new, costeffective and more widely available approach to measure the oxygen isotope ratio in water molecules, H218O/H216O (d18O), and are used increasingly to measure d18O in the world’s oceans. Here, we present results froman interlaboratory comparison designed to evaluate the quality of CRDS-derived measurements, and theirconsistency with values measured by isotope ratio mass spectrometry (IRMS).