Some Aspects of the Use of Py–gc–ms to Investigate the Composition of the Aromatic Fraction of Hard Coal Pyrolysates

Py–GC–MS has been used to compare the extent of transformation of hard coals from a bed thermally affected by magmatic intrusion. The coal samples under investigation originated from bed 416 of the “Sośnica” coal mine (USCB, Poland). They were taken at different distances from the intrusion and were thus subjected to different amounts of metamorphosis. To assess changes in chemical structure caused by the intrusion comparative analysis was performed by GC–MS of pyrolysates obtained at different temperatures – 358, 480, 610, 770, and 980°C. Comparisons were based on the distribution of aromatic compounds, chiefly naphthalene and its methyl derivatives. The trend was for the amount of methyl substitution of the naphthalene rings to decrease with increasing temperature with, moreover, a relative preference for the more stable β substitution position rather than the α position. Some comparative numerical data, ratios of the intensities of the GC–MS peaks, were calculated.