New Chinese National Reference Materials for Hydrogen and Oxygen Isotopes in Water

Abstract

The Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences recently prepared four certified reference materials for hydrogen and oxygen stable isotopes in water, which are called ‘China Standard Water' (CSW)‐HO1–HO4 (hereafter referred to as HO1–HO4). These reference materials are intended for calibration purposes and provide reference values of their relative difference in 2H/1H and 18O/16O isotope‐amount ratios expressed in delta notation, normalised to the VSMOW–SLAP scale. The certified values of the reference materials were determined by an interlaboratory comparison of results from eleven participating laboratories. This paper describes in detail the production and certification procedure of the four reference materials. The first analytical data for the reference materials are also provided using a variety of analytical techniques, namely CO2–H2O equilibration and laser spectroscopy for δ18O and Cr reduction, as well as H2–H2O equilibration, laser spectroscopy, and high‐temperature conversion for δ2H. The reference values for materials HO1–HO4 and their associated uncertainties are assigned.