Compar ison of Carbon Isotopic Composition of the Saturated Hydrocarbons before and after Complexation 5à Molecular Sieve

Key words: 
• carbon isotope /
• 5à /
• molecular sieve /
• n-alkane /
• Soxhlet extraction

Abstract: In order to find the difference of the isotopic composition of different organic compounds before and after comp lexation, the autogamy standard sample is performed by à molecular sieve adsorp tion to study the variation of the isotope compositions of n-alkanes, isoalkanes and cyclanes. Although samples were in a hot reflux for a long time at 85℃ in the experiment, and 5à molecular sieve of the adsorbed sample was acidized by hydrofluoric acid, the analyticalmethod was tested to have little influence on carbon isotopic composition of the saturated hydrocarbons before and after complexation. This paper also discussed the method to analyze the individual hydrocarbon isotopic composition from crude oil and coal rock samples. On the basis of the previouswork, the mini-sized Soxhlet extraction setwith a hot reflux device is adopted to enhance the recovery of samples and diminish the loss of light components in the tested samples.