Characterization of polyaromatic structures in coal extracts and coal derived liquid by UV fluorescence

A structural analysis of the organic part of French coals of different rank is performed by UV fluorescence spectroscopy (synchronous excitation-emission technique). The spectral study was made on different extracts (hexane, toluene, tetrahydrofurane and pyridine extracts) obtained by ultrasonic multiple step extraction. On a spectroscopic basis it is thus possible to show clearly the differences between coals of different rank and bring out the notion of a «fingerprint» characteristic of a given coal