Identification of partially hydrogenated nitrogen-containing polycyclic aromatic hydrocarbons in coal liquids by tandem mass spectrometry

A nitrogen-base extract of a coal liquid has been examined for partially hydrogenated nitrogen-containing polynuclear aromatic hydrocarbons (PAH) using mass spectrometry/mass spectrometry. Neutral loss scans coupled with trifluoroacetyl derivatization of the sample allowed differentiation of the partially hydrogenated components from other nitrogen-containing species present. Four different partially hydrogenated nitrogen-containing PAH structures were detected, including tetrahydroquinolines, tetrahydroazaacenaphthalenes, and tetrahydrobenzoquinolines. Some of the other nitrogen-containing constituents which were identified include anlines, aminonaphthalenes, aminophenanthrenes/aminoanthracenes, quinolines, and carbazoles.