Quantitative compositional analysis of Estonian shale oil using comprehensive two dimensional gas chromatography

- Polar × mid-polar column combination GC × GC improves separation of highly polar oxygen containing compounds
- Estonian pyrolysis shale oil contains 39 wt.% of oxygen containing compounds
- Carbon number ranges from C3 to C26, C< 21 account for 95 wt.% of the sample
- Olefins and cycloalkanes, with concentrations of 17.5 wt.% and 16.8 wt.% respectively, are the major chemical classes

An Estonian pyrolysis shale oil has been characterized using comprehensive two dimensional gas chromatography (GC × GC) coupled to a flame ionization detector (FID) and time of flight mass spectrometer (TOF-MS). Oxygen containing compounds were abundant and the following classes were identified: benzenediols, hydroxybenzofurans, phenols, ketones, and naphthols. The large peak overlap observed for oxygenates with the hydrocarbon matrix using a non-polar × polar column combination made identification and quantification difficult. A methodology based on the more selective separation using a polar × non-polar and polar × mid-polar column configurations was developed and tested. The obtained bidimensional resolution confirms that the method provides an improved separation of unsaturated hydrocarbons, mid-polar and even highly polar oxygen containing compounds. The use of an internal standard methodology allowed complete quantification of the pyrolysis shale oil both by carbon number and chemical class.