Reduction of microliter amounts of water with manganese for D/H isotope ratio measurement by mass spectrometry

For the measurement of deuterium content in natural waters, a rapid and precise analytical technique has been developed for the quantitative conversion of water to hydrogen with manganese as reducing agent. It was found that 8 mu l of water, 0.8 g of Mn, and a reaction time of 40 minutes at 520 degrees C are the optimal conditions for the conversion reaction. Each sample is reduced individually in a high vacuum reaction vessel with a Teflon stopcock. A set of six samples can be prepared at one time. Analyses of standard water samples gave a reproducibility of +/-1%(1 sigma).