129I/127I ratios were investigated as a potential for dating and tracing studies of crude oil systems. 129I/127I ratios were measured using a tandem accelerator mass spectrometer located at the University of Rochester. Carrier-free methods for AgI preparation are discussed for formation waters, petroleum, and source and reservoir rocks. Formation water extractions include the use of oxidizing and reducing agents to extract iodine into carbon tetrachloride. Samples prepared in this way gave good ratio measurements with no contamination. Two methods for iodine extraction from petroleum are employed. The first is a sodium biphenyl extraction which will extract up to 90% of iodine but has serious limitations due to contamination of the solvent. The second method for petroleum is a combustion method which can recover at least 50% iodine with minimal contamination if the proper precautions are observed. Only 10% of iodine can be recovered in the rock samples at this time using a nitric acid digestion in a closed system and collecting iodine in carbon tetrachloride from the vapors.
Library of Congress Subject Headings
Radiosotopes in petroleum engineering; Iodine--Isotopes; Extraction (Chemistry)
Department, Program, or Center
School of Chemistry and Materials Science (COS)
Tullai, Sharon, "Extraction methods for iodine from crude oil systems for the determination of 129I/127I ratios" (1988). Thesis. Rochester Institute of Technology. Accessed from
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