1988 Volume 37 Issue 2 Pages 94-98
Although it has been considered that the V and Ni contained in crude oil are present in various chemical states or forms, just the total concentration of either metal has been determined by conventional manner of analysis. In this paper is described the feasibility of fractional determination of V and Ni in crude oil sample by combination of size exclusion chromatography (SEC) with graphite furnace AAS. A Mideastern heavy crude oil sample was fractionated into malten and asphalten by shaking with hexane, and then each of resulting substances was submitted to SEC separation. The column effluent was fractionated. The V and Ni contents of respective fractions were determined by AAS, and the distribution of these metals was represented in chromatogram by histograms. It has been clarified that both V and Ni are present in the crude oil as a variety of organic chemical forms in a wide range of molecular weight up to 103 level, and also that these metal-containing species are fractionated with more extent to asphalten than to malten.
