A new continuous flow isotope ratio mass spectrometry system for the analysis of delta2H, delta17O and delta18O of small (120 microg) water samples in atmospheric applications.

Abstract

A new continuous-flow system for the analysis of the complete stable isotopic composition of water vapor has been developed. The sample size is reduced to only 120 microg (identical with 120 nL of liquid substance) of water, yielding precisions of about 0.7, 1.3 and 7 per thousand for delta17O, delta18O and delta2H, respectively. The total time for the analysis of a sample is about 150 min including purging times. Oxidized steel surfaces can be a source of memory effects which can be corrected for. The system is predestined for atmospheric applications in the tropopause region, as the sample can be directly introduced into the system from a cryogenic trap.