Print Email Facebook Twitter Technical Note: Evaluation of between-sample memory effects in the analysis of ?2H and ?18O of water samples measured by laser spectroscopes Title Technical Note: Evaluation of between-sample memory effects in the analysis of ?2H and ?18O of water samples measured by laser spectroscopes Author Penna, D. Stenni, B. Sanda, M. Wrede, S. Bogaard, T.A. Michelini, M. Fischer, B.M.C. Gobbi, A. Mantese, N. Zuecco, G. Borga, M. Bonazza, M. Sobotkova, M. Cejkova, B. Wassenaar, L.I. Faculty Civil Engineering and Geosciences Department Water Management Date 2012-10-31 Abstract This study evaluated between-sample memory in isotopic measurements of ?2H and ?18O in water samples by laser spectroscopy. Ten isotopically depleted water samples spanning a broad range of oxygen and hydrogen isotopic compositions were measured by three generations of offaxis integrated cavity output spectroscopy and cavity ringdown spectroscopy instruments. The analysis procedure encompassed small (less than 2 for ?2H and 1 for ?18O) and large (up to 201 for ?2H and 25 for ?18O) differences in isotopic compositions between adjacent sample vials. Samples were injected 18 times each, and the betweensample memory effect was quantified for each analysis run. Results showed that samples adversely affected by betweensample isotopic differences stabilised after seven–eight injections. The between-sample memory effect ranged from 14% and 9% for ?2H and ?18O measurements, respectively, but declined to negligible carryover (between 0.1% and 0.3% for both isotopes) when the first ten injections of each sample were discarded. The measurement variability (range and standard deviation) was strongly dependent on the isotopic difference between adjacent vials. Standard deviations were up to 7.5for ?2H and 0.54for ?18O when all injections were retained in the computation of the reportable ?-value, but a significant increase in measurement precision (standard deviation in the range 0.1 –1.0 for ?2H and 0.05– 0.17for ?18O) was obtained when the first eight injections were discarded. In conclusion, this study provided a practical solution to mitigate between-sample memory effects in the isotopic analysis of water samples by laser spectroscopy. To reference this document use: http://resolver.tudelft.nl/uuid:0409d7ed-2114-4b96-bf16-864190b6b822 DOI https://doi.org/10.5194/hess-16-3925-2012 Publisher European Geosciences Union (EGU) ISSN 1027-5606 Source http://www.hydrol-earth-syst-sci.net/16/3925/2012/ Source Hydrology and Earth System Sciences, 16 (10), 2012 Part of collection Institutional Repository Document type journal article Rights © 2012 The Author(s)CC Attribution 3.0 License Files PDF 284778.pdf 2.21 MB Close viewer /islandora/object/uuid:0409d7ed-2114-4b96-bf16-864190b6b822/datastream/OBJ/view