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Improved throughput for δ18O and δD measurements of water with Cavity Ring-Down Spectroscopy

Literature Reference

Dr. Keren Drori, Senior Product Manager, Picarro

December 13th, 2021

Oxygen (18O/16O) and deuterium (D/H) isotopes are a widespread tool to trace physical and chemical processes in hydrology and biogeosciences. Precision and throughput are key parameters for water isotope analysis. Here, we will present two new methodologies for the Picarro L2130-i Cavity Ring-Down Spectroscopy (CRDS) water isotope analyzer that allow the user to increase the throughput with compromising data quality. The Picarro Express Method now distinguishes between a memory reduction stage and a sample analysis stage and allows the user to measure up to 50 samples per day while maintaining the excellent precision of CRDS (i.e., 0.01‰ for δ18O and 0.05‰ for δD). This corresponds to doubling the throughput compared to the standard Picarro methodology. The Picarro Survey Method makes use of ultrafast injections and sorts the samples by their measured isotopic values, enabling a powerful new strategy to reduce memory effects. We present these different measurement strategies to increase the throughput for routine water isotope analysis. The improved methodologies do not require any hardware changes and are solely based on modifications of the injection procedure.