High-resolution gas chromatography and high-resolution gas chromatography/mass spectrometry study of the volatile fraction obtained from high-inertinite Brazilian coal by supercritical fluid extraction

This work presents the results of a study involving a high-inertinite coal from Amando Simoes Mine, located in Parana state (Brazil). The organic matt er was extracted in a supercritical fluid (static mode) apparatus using tol uene as the extraction fluid in the presence of hydrogen. The variables wer e studied using a 2(3) factorial design (two levels for three variables: te mperature, reaction time, and pressure) with three center points. The liqui d coal extracts obtained were fractionated by preparative liquid chromatogr aphy into eight fractions (PLC-8) by using an adequate series of eluents. E ach eluted fraction was collected and quantified by gravimetry. The relativ e fraction yields were used to calculate the influence of the variables and their interaction in the factorial design. All hydrocarbon-rich fractions were analyzed by high-resolution gas chromatography (HRGC)-fluid ionization detection and HRGC-mass selective detection (MSD). The characterization of chemical classes of interest in the collected fractions was carried out us ing HRGC-MSD in the extracted ion mode. This approach allowed fine monitori ng of compounds of interest by their characteristic m/z values and was a fa st and very selective setup for detection of specific compounds in a very c omplex matrix. (C) 1999 John Wiley & Sons, Inc.