Ni and V occur in the polar fraction of crude oils and have geochemical interest. A method was developed for isolating and quantifying these metals associated with organic compounds like porphyrins, using liquid chromatography and inductively coupled plasma mass spectrometry (ICPMS). The oil fraction containing paraffins, aromatics and polars was separated using a glass column of 25 cm x 2.5 cm filled with silica gel. An automatic elution program was used to create a solvent elution gradient of increasing polarity. The column eluate were analyzed by UV-vis spectrophotometry and the chromatograms obtained showed the separation of three fractions, which were then analyzed separately by ICPMS. The ICPMS sample introduction system consisted of a concentric Teflon micronebulizer coupled to a refrigerated spray chamber set to - 14 ºC. Oxygen was introduced into the nebulization gas flow to prevent de formation of carbon at the instrument interface. Operational conditions were optimized by experimental design. The optimum gas flow rates were 0.46 L min - 1 (Ar) and 0.1 L min - 1 (O2), at 1350 W.