ACCURATE DETERMINATION OF NITROGEN CONCENTRATIONS BY STATIC VACUUM MASS-SPECTROMETRY

Herein is described a mass spectrometer and associated extraction line for accurate determination of the abundance of nitrogen in a variety of samples including meteorites, lunar samples, diamonds, organic compounds and ammonium-bearing rocks and minerals. The error is of the order of +/-5% or less for samples containing between 22 wt% N and a few parts per million of N. Perhaps the most important control on the accuracy of the results is the reliability of the N content of the materials used for standardization. Whilst commercially available standards can be used for samples containing N at the percentage level, for samples containing trace amounts of N, reference materials need to be synthesized in the laboratory prior to analysis. We strongly urge that a new international reference material be synthesized for use during determination of trace abundances of N.