HIGH-PRECISION DETERMINATION OF H-2 H-1 IN H-2 AND H2O BY CONTINUOUS-FLOW ISOTOPE RATIO MASS-SPECTROMETRY/

The major obstacle to accurate and precise measurement of H-2/H-1 in H -2 by continuous-now, isotope ratio mass spectrometry has been the int erference of the He-4(+) carrier peak with the neighboring (HH+)-H-2-H -1 peak, This has been overcome casing a novel mass spectrometer with high dispersion, giving an abundance sensitivity at m/z 3 of <1 ppm. S amples of H-2 with natural abundance H-2/H-1 can be analyzed routinely in <2 min with a precision of +/-1.5 parts per thousand. In combinati on with the equilibration of H2O with H-2, this technique provides a f ast, accurate method of analysis of water, with a precision of +/-3.0 parts per thousand at natural abundance. There is no measurable memory between samples of either water or H-2 gas. The technique is accurate over a wide range of enrichment and is useful for tracer experiments as well as natural abundance studies.