APPLICATION OF LASER-INDUCED FLUORESCENCE OF COAL EXTRACTS FOR DETERMINING RANK

The aromatic hydrocarbon fractions from the solvent extracts from a ra nk suite of eight vitrinite concentrates have been analyzed using a la ser fluorescence spectrometer. A nitrogen laser (with emission at 337 nm) and a tunable dye laser (with emission set at 405 nm; IBOP dye) ar e used as excitation sources for the fluorescence analyses. The fluore scence emission spectra were recorded with the use of a Boxcar signal averager. Based upon comparison with aromatic reference compounds, sev eral aromatic compounds in the extract fractions have been tentatively identified on the basis of their emission peaks. Three new rank param eters are proposed based on emission peak intensity ratios (I396/I475 for N2-laser excitation and I447/I505 for dye-laser excitation) and an area ratio (S457/S414). These parameters are believed to be capable o f improving the maturity assessment of organic matter, especially that contained in marine rocks where vitrinite is rare or absent.