Evaluation of the performance of cryogen-free thermal modulation-based comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOFMS) for the qualitative analysis of a complex bitumen sample

Abstract

Historically, one-dimensional gas chromatography combined with mass spectrometry (GC/MS) has been employed in the analysis of petrochemical samples such as diesel, crude oil and bitumen. With increasingly complex samples, obtaining detailed information can be difficult with this method due to the large number of coelutions. By implementing comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC-TOFMS), the limitations of GC/MS can be overcome, due to the ability of this method to separate mixtures using two different separation mechanisms and obtain full mass spectra. Furthermore, this enables an investigation of biomarkers, compounds which aid in the identification of geological and environmental processes, potentially differentiating crude oil samples. Cryogenic-based thermal modulators are typically used for this application due to their superior focusing effect; however, some platforms require expensive cryogenic consumables. The solid-state modulator (SSM), a cryogen-free thermal platform, was employed for the first time for the group and biomarker analysis of Alberta oil sands bitumen. Evaluation of the SSM performance was based on published literature data on bitumen analysis. Extracted ion chromatograms (EIC) and molecular ion peaks were used for the confirmation of the groups’ and individual’s analytes. Identification of the characteristic biomarkers responsible for determining thermal maturity, source rock or oil origin was achieved. These results indicate the successful analysis of bitumen by consumable-free, solid-state modulation-based GC×GC-TOFMS.