PREPARATIVE THIN-LAYER CHROMATOGRAPHY AND HIGH RESOLUTION MASS SPECTROMETRY OF CRUDE OIL CARBOXYLIC ACIDS

A carboxylic acid fraction of high interfacial activity isolated from a California crude oil was subjected to preparative thin-layer chromatography (TLC). The complexity of this fraction was reduced by TLC to about 1500 compounds, many of which belong to homologous series. Proof for absence of contamination was obtained. High resolution mass spectrometry studies of these carboxylic acids and derived trihydroperfluoroheptyl esters were performed. Based on exact masses of parent ions and fragments and on relative ion abundances, the presence of terpenoid, polynuclear saturated and mono- and polynuclear aromatic as well as naphtheno-aromatic ring structures is indicated. Comparison of acids and esters shows that the most abundant species contain 2, 3, 4, and 5 saturated rings and fused polynuclear structures. The presence of many compound classes of carboxylic acids not discovered previously in petroleum is postulated. © 1969, American Chemical Society. All rights reserved.