Comparison of mass spectrometric and nuclear magnetic resonance techniques for hydrocarbon type determination

Abstract

The hydrocarbon type content of petroleum fractions has traditionally been determined using different techniques, but often with poor agreement among the various results for a given sample. In this study, thre'e different fractions were analyzed using mass spectrometric (MS), 1 nuclear magnetic resonance (NMR), and fluorescent indicator analysis (FIA) techniques. The 13 C and 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 5pecial 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 this ; atomic data can be correlated with the fractions' properties, the NMR results on a molecular basis are uncertain because of the number of assumptions involved