A new isotopic reference material for stable hydrogen and oxygen isotope-ratio measurements of water—USGS50 Lake Kyoga Water

Rapid Communications in Mass Spectrometry
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Abstract

Rationale

As a result of the need for isotopic reference waters having high δ2HVSMOW-SLAP and δ18OVSMOW-SLAP values for daily use, especially for tropical and equatorial-zone freshwaters, a new secondary isotopic reference material for international distribution was prepared from water collected from Lake Kyoga, Uganda.

Methods

This isotopic reference lakewater was filtered through a membrane with 0.2-µm pore size, homogenized, loaded into glass ampoules that were sealed with a torch and autoclaved to eliminate biological activity, and measured by dual-inlet isotope-ratio mass spectrometry. This reference material is available in a case of 144 glass ampoules each containing 5 mL of water.

Results

The δ2H and δ18O values of this reference material are +32.8 ± 0.4 and +4.95 ± 0.02 mUr (milliurey = 0.001 = 1 ‰), respectively, relative to VSMOW, on scales normalized such that the δ2H and δ18O values of SLAP reference water are, respectively, −428 and −55.5 mUr. Each uncertainty is an estimated expanded uncertainty (U = 2uc) about the reference value that provides an interval that has about a 95 % probability of encompassing the true value.

Conclusions

This isotopic reference material, designated as USGS50, is intended as one of two reference waters for daily normalization of stable hydrogen and oxygen isotopic analysis of water with an isotope-ratio mass spectrometer or a laser absorption spectrometer, of use especially for isotope-hydrology laboratories analyzing freshwater samples from equatorial and tropical regions.

Study Area

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title A new isotopic reference material for stable hydrogen and oxygen isotope-ratio measurements of water—USGS50 Lake Kyoga Water
Series title Rapid Communications in Mass Spectrometry
DOI 10.1002/rcm.7369
Volume 29
Issue 21
Year Published 2015
Language English
Publisher Wiley
Contributing office(s) National Research Program - Eastern Branch
Description 5 p.
First page 2078
Last page 2082
Country Uganda
Other Geospatial Lake Kyoga
Online Only (Y/N) N
Additional Online Files (Y/N) N
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