LASER MICROPYROLYSIS GAS-CHROMATOGRAPHY MASS-SPECTROMETRY OF COAL

The focused output of a pulsed ruby laser is used for the in-situ pyro lysis of individual coal macerals. This study couples laser pyrolysis with gas chromatography/mass spectrometric analysis allowing for the d etection of neutral, volatile organic compounds formed in coal pyrolys is. Typically, released pyrolyzates from the vitrinite of a sub-bitumi nous coal and a coalified log of lignite rank include a wide distribut ion of aliphatic compounds (predominantly alkanes) in addition to arom atic compounds such as alkylbenzenes, phenols, and naphthalenes. The p roduction of such compounds highlights the efficiency of laser radiati on as a source for coal pyrolysis. The distribution of the detected co mponents in the pyrograms is typical of compounds produced from vitrin ite-rich coals by other pyrolysis methods. Differing pyrolyzates popul ations, including subtle intensity fluctuations for common product cla sses, allows for chemical distinction between the two samples examined . The potential of this technique for the in-situ chemical investigati on of individual coal macerals which may be present in very small amou nts within the parent coal is established.