HPLC separation and characterization of nickle geoporphyrins

HPLC separation of nickel geoporphyrin homologues and isomers has been markedly enhanced by a number of modifications of previously disclosed methods. A general, more efficient and reproducible method has been developed. A C18 3-micron reverse phase column with a programmed gradient binary mobile phase composed of solvent A which is methanol, water and solvent B which consists of methanol modified by the addition of powerful ligand; a consistent ratio of organic salt is added into this solvent system to increase ionic strength of mobile phase. Straightforward HPLC separations of some marine sediment and oil shale extracts (nickel porphyrins) without demetallation have been successfully achieved. Most attention has been focused on Cowboy Gilsonite and Bakken oil-shale. Individual fractions have been collected and analyzed by UV-VIS, NMR, Mass spectrometry. Known compounds were used for co-chromatographic and spectroscopic reference.