Separation and Characterization of Vanadyl Porphyrins in Venezuela Orinoco Heavy Crude Oil

Abstract

Venezuela Orinoco heavy crude oil was sequentially separated into several subfractions to determine the contents and types of vanadyl porphyrins contained in the products. Vanadium contents in each subfraction were detected using an atomic absorption spectrometer (AAS) combined with the characterization of vanadyl porphyrins by ultraviolet–visible (UV–vis) spectroscopy and positive-ion electrospray ionization (ESI) Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS). Six types of petroleum vanadyl porphyrins, which have been identified previously, were well-characterized with the detailed fractionation. Three new series of vanadyl porphyrins corresponding to molecules of CnHmN4VO2, CnHmN4VO3, and CnHmN4VO4, respectively, were identified in addition to the six known types of vanadyl porphyrins.