POLYCYCLIC AROMATIC SULFUR HETEROCYCLES .4. DETERMINATION OF POLYCYCLIC AROMATIC-COMPOUNDS IN A SHALE OIL WITH THE ATOMIC-EMISSION DETECTOR

A method for the determination of alkylated benzothiophenes and dibenzothiophenes, naphthothiophenes and several other aromatic compounds in a shale oil as an example for a very complex matrix is presented. Fluorinated aromatics were used as internal standards. The isolated aromatic fraction of the shale oil was separated according to the number of aromatic rings. Oxidation of the two-ring compounds led to benzothiophene sulfones which were further separated by liquid chromatography according to the number of side-chain carbon atoms. The three-ring compounds were separated into a sulfur aromatics-free and a sulfur aromatics-containing fraction using palladium chloride/silica gel. The GC stationary phases necessary for the quantification of all compounds of interest are discussed. Quantitative data obtained with an atomic emission detector are given for 22 compounds in the shale oil. Conventional quantification, without the elaborate separations described here, would overestimate the phenanthrene content of the shale oil by ca. 15% and that of dibenzothiophene by nearly 50%.