Improving the Accuracy of Stable Isotope Analysis of Atmospheric and Soil Trace Gases Using Automated Multiple Sampling Combined with a Standard Trace Gas Pre-Concentration System
by
Francois Fourel
Micromass UK Ltd, Floats Rd, Manchester, UK
Coauthors: Mounier, L.(Micromass UK Ltd, Floats Rd, Manchester, UK), Davis, S. (Micromass UK Ltd, Floats Rd, Manchester, UK), Torn, M. (LBNL, 1 Cyclotron Rd, Berkeley, CA, USA), Phillips, A. (Micromass UK Ltd, Floats Rd, Manchester, UK)

Due to the increasing interest in soil / atmosphere interactions, the application of stable isotope analysis of atmospheric trace gases has greatly increased in importance.

Traditionally, high precision isotopic analysis of trace gases has been performed using dual inlet IRMS. Because of the extremely low concentrations of analyte, this approach is not always freezable when looking at soil or atmospheric trace gases. It has, therefore, become necessary to rely on the highly sensitive method of continuous flow mass spectrometry, which although offering low detection limits is often perceived as less accurate than dual inlet analysis. Although current manufactures specify that trace gas systems can provide precision of 0.5 per mil for CO2, N2O and CH4, it is possible to significantly improve these figures by multiple sub sampling and analysis of single soil and atmospheric gases. This study will show how a standard trace gas system can be interfaced with a 16 bottle auto-sampler, permitting multiple sub sampling and the addition of internal NOAA standards to each gas sample. The resulting increase in precision and accuracy will be discussed.

Date received: May 4, 2001

Copyright © 2001 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cahi-77.