Open Tubular Supercritical Fluid Chromatography (ot-SFC) Applied to the Separation of Coal-Derived Products Obtained by Supercritical Fluid Extraction (SFE)

Abstract

This work describes the construction and evaluation of a simple and versatile capillary supercritical fluid chromatographic (SFC) system and its application to the analysis of liquid fuels obtained by SFE. The modular supercritical fluid chromatography (SFC) system uses a syringe pump, a fused silica capillary column (100 μm i.d., coated with a 0.2-μm thick film of 5% phenylpolymethylsiloxane), a FID detector, and a high pressure injection valve with a 60-nL internal loop. Coal-derived samples were obtained by supercritical fluid extraction (SFE) of a Brazilian high-inertinite coal from Amando Simoes mine, located in Parana state (Brazil) using toluene as solvent and operating in the static mode. SFE was followed by preparative liquid chromatography fractionation into eight discrete fractions (PLC-8 method). Two of those fractions (F-2 and F-8) were used to evaluate the proposed set-up. The system described proved to be simple, easy-to-use, and versatile when used in the analysis of a range of samples from low molecular weight-low volatility (F-2) to higher molecular weight-high polarity asphaltols (F-8).