Identification of some polycyclic nitrogen-containing compounds in coal-derived oil

A systematic method for the identification of aza-arenes in coal-derived oil was developed. The basic nitrogen-containing substances were extracted with 6 M hydrochloric acid and fractionated sequentially by using gel chromatography and thin-layer chromatography (TLC) on an alumina plate. The aza-arenes in these fractions were separated by using glass capillary gas chromatography. Individual compounds in the column effluent were trapped in a system consisting of a valve for flow switching and a trapping tube made from a glass capillary. The fluorescence spectra of nanogram to subnanogram amounts of trapped compounds were measured. Some attempts were made to identify components based on their TLC RF values and their fluorescence spectra, in addition to their mass spectra.