The present invention provides a method for preparing a VOC sample for carbon and chlorine isotope ratio analysis by mass spectrometer. A VOC sample is placed in a combustion tube and reacted with CuO to form CO.sub.2 and CuCl. The CO.sub.2 is then extracted and analyzed for the carbon isotope ratio. The CuCl is separated from the excess CuO and reacted with CH.sub.3 I to form CH.sub.3 Cl, extracted and analyzed for chlorine isotope ratio.
CONTRACTUAL ORIGIN OF THE INVENTION
The United States Government has rights in this invention pursuant to Contract Number W-31-109-ENG-38 between the U.S. Department of Energy and the University of Chicago representing Argonne National Laboratory