VSMOW2 , Water

2H and 18O in water samples , Water

VSMOW2 (Vienna Standard Mean Ocean Water 2) is an international measurement standard for stable isotope analysis. This water material was prepared at the IAEA Isotope Hydrology Laboratory in 2006 to replace the exhausting VSMOW material. VSMOW2 was mixed from carefully calibrated distilled natural water samples in order to obtain a stable isotopic composition as similar as possible to that  of the original VSMOW. Five selected laboratories provided calibration measurements in direct comparison to VSMOW. All δ-values will continue to be reported in the VSMOW/SLAP scale, using VSMOW2 and SLAP2 as calibration materials with their assigned stable isotope reference values.

Analyte Value Unit SD R/I/C
δ18O 0.02 
δ2H 0.3 

(SD) Standard uncertainty at 1 sigma level calculated from results of calibrations performed at five laboratories.
(R/I/C) Classification assigned to the property value for analyte (Recommended/Information/Certified)


  1. GRÖNING, M., VAN DUREN, M., ANDREESCU, L., Metrological characteristics of the conventional measurement scales for hydrogen and oxygen stable isotope amount ratios: the δ-scales. In: Combining and Reporting Analytical Results, Eds. A. Fajgelj, M. Belli, U. Sansone. Proceedings of an International Workshop on “Combining and reporting analytical results: The role of traceability and uncertainty for comparing analytical results”, Rome, 6-8 March 2006. Royal Society of Chemistry (2007) 62-72.

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