Determination of vanadium in petroleum crudes and fuel oils by gas chromatography

A method is described for determining levels of vanadium as low as 0.1 μg g^-1 in petroleum oils by gas chromatography with flame-ionization detection. The method involves decomposition of the oils, derivatization and solvent extraction of vanadium as the chelate, 2,2,2',2'-tetramethyl-5,5'-(ethane-1,2-diyldiimino)bis(hex-4-en-3-onato)-(2-)] oxovanadium(IV), followed by gas chromatography on a non-polar (SE-30) column. The procedure is applied to a variety of samples, including standard reference and fuel oils used in an interlaboratory study. The results are compared with those of emission spectrography and two standard methods. The new procedure can be extended to the selective, simultaneous detection of copper, nickel and vanadium in such samples.