Hydrocarbon class type distribution of crude oils by high performance liquid chromatography

High performance liquid chromatography (HPLC) provides a rapid analytical technique for chemical group type separation for evaluating crude oils. Seven crude oils of different origins and a technical blend of these crudes were taken up for this study. Crude oils were separated into total saturates and total aromatics on amino bonded silica column through HPLC system using UV and RI detectors. The quantitation of all class types were carried out by applying the response factors of separated concentrates from the technical blend of crude oils and calculating their response factors. The precision and the accuracy of the method was demonstrated by determining the standard deviation for the peak areas using pure compounds and comparison of HPLC procedure with their gravimetric data obtained by open column chromatography on technical blend of crude oils. The method is simple, accurate and provides compound class type analysis with microgram sample and is suitable for quick compositional surveys of crude oils. It uses a single solvent elution, requires minimum sample preparation and the time required for single analysis is less then an hour. Therefore, the method can be adapted for routine analysis of crude oils and streams from various processes.