Preparation of a novel chromatographic material and its application for spectroscopic characterization of aromatics in crude oil

Abstract

Petroleum analysis presents many unique challenges as a result of the chemical complexity of petroleum composition. In the present work a novel chromatographic material has been developed and utilized to separate crude oils. A total number of 13 fractions have been collected using different solvent mixtures with increasing proportions of chloroform. UV and IR spectroscopy has been employed to show that the size of the aromatic ring system increases and the extent of molecular branching decreases with elution gradient. This observation suggests that intermolecular non-covalent π-π interactions between the material and the sample molecules are critical to the separation. This novel method for sequencing petroleum molecules based on the size of the aromatic ring systems has been applied to the 2D off-line analysis of crude oil samples. The 2D on-line separation (NPLC × NPLC) has been simulated by 2D off-line separation. A total number of 38 fractions have been obtained with two SPE columns based on the molecular branching and the aromatic ring system size. The chemical information obtained in this study of North Sea crude oil is complementary to standard SARA analysis. The material supports a potential solution to overcome the challenges of tandem NPLC and has demonstrated a new approach to the separation of crude oils into discrete compound classes.

Keywords

• Crude oil
• 2D separation
• Spectroscopy
• Chromatography
• Aromatics
• Petroleum