IDENTIFICATION AND QUANTIFICATION OF NITROGEN AND SULFUR-COMPOUNDS IN CATALYTICALLY CRACKED HEAVY GAS OILS BY ISOBUTANE/CI GC/MS AND GC USING SELECTIVE DETECTORS

Nitrogen- and sulfur-containing alkyl homologues of indole, carbazole, benzocarbazoles, benzothiophene, dibenzothiophene, and tribenzothiophenes are identified and quantified in fractionated catalytically cracked heavy gas oils. Four boiling fractions, 500 degree to 600 degree F, 600 degree to 700 degree F, 700 degree to 800 degree F, and 800 degree to 900 degree F, are analyzed by isobutane chemical ionization (CI) gas chromatography/mass spectrometry (GC/MS) and GC techniques in which nitrogen and sulfur selective detectors are employed. The total nitrogen and the total sulfur values obtained by organic elemental analysis are included for comparison. Comparison of quantitative results obtained by the three different techniques shows excellent agreement.