Measurement of extremely 2H-enriched water samples by laser spectrometry: application to batch electrolytic concentration of environmental tritium samples

RATIONALE: Natural water samples artificially or experimentally enriched in deuterium (H-2) at concentrations up to 10,000ppm are required for various medical, environmental and hydrological tracer applications, but are difficult to measure using conventional stable isotope ratio mass spectrometry. METHODS: Here we demonstrate that off-axis integrated cavity output (OA-ICOS) laser spectrometry, along with H-2-enriched laboratory calibration standards and appropriate analysis templates, allows for low-cost, fast, and accurate determinations of water samples having delta H-2(VSMOW-SLAP) values up to at least 57,000%(similar to 9000 ppm) at a processing rate of 60 samples per day. RESULTS: As one practical application, extremely H-2-enriched samples were measured by laser spectrometry and compared to the traditional H-3 Spike-Proxy method in order to determine tritium enrichment factors in the batch electrolysis of environmental waters. Highly H-2-enriched samples were taken from different sets of electrolytically concentrated standards and low-level (< 10 TU) IAEA inter-comparison tritium samples, and all cases returned accurate and precise initial low-level H-3 results. CONCLUSIONS: The ability to quickly and accurately measure extremely H-2-enriched waters by laser spectrometry will facilitate the use of deuterium as a tracer in numerous environmental and other applications. For low-level tritium operations, this new analytical ability facilitated a 10-20 % increase in sample productivity through the elimination of spike standards and gravimetrics, and provides immediate feedback on electrolytic enrichment cell performance. Copyright (C) 2016 John Wiley & Sons, Ltd.