Mass-spectrometric study of nitrogen compounds from petroleum distillates

A mass-spectrometric method is given for the determination of the pyridine-quinoline type distribution, including subdistribution according to naphthenicity, in corresponding concentrates from petrolium fractions. Its results are in good agreement with those of ultraviolet spectrometry. In non-base nitrogen concentrates indole-carbazole distributions can be determined similarly. The method uses peak intensity summations comprising the parent and parent-minus-one series, starting from the first naptheno-aromatic skeleton conceivable that is built up of condensed five-membered naptheno rings. It is based on current concepts on total ionization. The presence of mono- and dinaptheno-pyridines, mono-naptheno-quinolines and naptheno-carbazoles in oil fractions was demonstrated. Besides, basic nitrogen concentrates were obtained containing one sulphur atom per heteroaromatic ring system. Here,combined application of mass- and ultraviolet spectrometry before and after selective hydrogenation led to detailed conclusions regarding their heteroaromatic nucleus.