Abstract
A method to determine stable isotope ratios of atmospheric water vapor and carbon dioxide is presented. Simplified sampling and careful purification allow precise determination of isotope ratios. Air sample is collected in a plastic bag. The water vapor and carbon dioxide are recovered by pumping through cryogenic traps under atmospheric pressure. Hydrogen and oxygen isotope ratios are determined for small amount of atmospheric water vapor. Carbon and oxygen isotope ratios are determined for carbon dioxide purified from nitrous oxide. The analytical errors of the present method are practically similar to those of conventional methods.
