Optimization of the HPLC separation of aromatic groups in petroleum fractions

An experimental procedure was developed for improving the separation between the aromatic component groups in petroleum fractions by high performance liquid chromatography. The mobile phase composition, consisting of n-hexane, chloroform and isopropyl ether was optimized with respect to the resolution between the aromatic component groups and the analysis time. The overlapping resolution mapping scheme was used for the establishment of the optimum mobile phase composition. A solvent composition (95% n-hexane–5% isopropyl ether) was found to provide the best resolution of the aromatic components while the required analysis time is kept reasonably low (30 min). The method was subsequently applied to the analysis of gas oil samples and demonstrated better separation profile of the aromatic groups in comparison with experimental results previously reported.