Optimization of instrument setup and post‐run corrections for oxygen and hydrogen stable isotope measurements of water by isotope ratio infrared spectroscopy (IRIS)

Abstract

Light stable isotope analyses of hydrogen (2H/1H) and oxygen (18O/16O) of water are used in many terrestrial and marine aquatic studies. The advantage of using stable isotope ratios is that water molecules serve as ubiquitous and already present natural tracers. Within recent years, these analyses have been revolutionized by the development of new isotope ratio laser spectroscopy (IRIS) systems that are cheaper, more robust, and mobile compared with traditional isotope ratio mass spectrometry (IRMS). Although easier to operate, laser systems also need thorough calibration with international reference materials, and raw data need correction for analytical effects (i.e., memory and drift). This study presents modifications to the hardware for liquid water injection, an optimized sequence layout and a simple post‐run correction procedure. These protocols will maximize precision, accuracy, and sample throughput via an efficient memory correction. The number of injections per unknown sample can be reduced to 4 or less. This procedure meets the demands of faster throughput with reduced costs per analysis. Procedures presented here are based on real analyses. They were also verified by an international proficiency test and traditional IRMS techniques.

Warm-based basal sediment entrainment and far-field Pleistocene origin evidenced in central Transantarctic blue ice through stable isotopes and internal structures

“…The ratio of 18 O to 16 O and of deuterium to protonium was determined in ppm in relation to Vienna Standard Mean Ocean Water (VSMOW). Results were corrected for memory, drift and offset from the VSMOW scale using a low (−54.55‰; USGS49), mid-range (−13.39‰; Picarro 3C), and high standard (12.34‰; Picarro ER1) following the methods of Geldern and Barth (2012).…”

Recrystallization-induced oxygen isotope changes in inclusion-hosted water of speleothems – Paleoclimatological implications

“…Measurement drifts, reproducibility and memory effect (van Geldern and Barth, 2012) were tested under different conditions by measuring δD and δ…”

Approaches for Achieving Long-Term Accuracy and Precision of δ18O and δ2H for Waters Analyzed using Laser Absorption Spectrometers

“…9 By design, the samples and standards in Tables 1 and 5 span the terrestrial δ 2 H and δ 18 O range of natural waters to encompass all possibilities, an extreme testing scenario that is unlikely to be encountered in laboratories measuring smaller δ ranges of local water samples on a regular basis. Although untested, one might predict that a similarly designed systematic-performance test, but spanning a less extreme isotopic range (thus lowering betweensample memory impacts) and tailored toward what is actually required by the LAS user, could produce better results by further minimizing between-sample memory impact.…”