ISOTOPIC SEAWATER ANALYSIS USING CAVITY RING-DOWN SPECTROSCOPY: METHOD FOR REDUCING THE EFFECT OF SALTS ON THE MEASUREMENTS

Abstract:

High-salinity waters such as Seawater poses an operational and maintenance challenge to the measurements of water stable isotopes via Cavity Ring-Down Spectroscopy. As liquid samples are evaporated in the vaporizer peripheral before being sent to the CRDS analyzer, salt precipitates accumulate in the vaporizer chamber. As a result, the sample-to-sample memory performance degrades over time and frequent cleaning is required to maintain the peripheral performance and integrity.

To address this issue, earlier work showed that adding a metallic mesh liner into the injection port of the vaporizer could capture salt solids and protect the vaporizer chamber without affecting the sample’s isotopic composition and the measurement performance.

Additional long-term tests have been recently conducted with the new commercially available Salt Liner accessory to assess its efficacy. We demonstrated the longer stability of the sample-to-sample memory performance on various brine water measurements when compared to a system without the Salt Liner. We also established the guidelines in using, replacing, and cleaning the Salt Liner.