Comparison of mass spectrometry and nuclear magnetic resonance spectrometry for determination of hydrocarbon type

Abstract

The hydrocarbon-type content of petroleum fractions has traditionally been determined by using different techniques but often with poor agreement among the various results for a given sample. In this study, three different fractions were analyzed by using mass spectrometric (MS), nuclear magnetic resonance (NMR), and fluorescent indicator analysis (FIA) techniques. The /sup 13/C and /sup 1/H NMR results were first converted from an atomic to a molecular basis. The MS, NMR, FIA, and bromine number results are compared, with special attention given to the olefinic contents. The assumptions involved in, and limitations of, each technique are identified. The analysis of light fractions free of dienes, olefins, and heteroatom-containing species is best performed by MS methods. The atomic hydrogen and carbon distribution from the NMR method is found to be applicable to all samples examined. While these atomic data can be correlated with the properties of the fractions, the NMR results on a molecular basis are uncertain because of the number of assumptions involved.