Direct atomic-absorption determination of the Ni and V content in oil

Direct determination of nickel in xylene solutions of raw material for catalytic cracking with application of graphite furnace atomic absorption spectrometry

“…In GFAAS, a typical way to decrease the volatility of the analyte or to unify behavior of various analyte forms is by application of chemical modiers. A popular modier, Pd nitrate, 8,14,20,36,37 is not soluble in xylene and other solvents dissolving petroleum products. Therefore, Pd acetylacetonate, as in earlier studies, 20,37,41 was selected for analysis in the present work.…”

“…GFAAS has been used for Ni determination in petroleum and its products since the early 70s. [7][8][9][10][11][12][14][15][16][17][18][19][20][21][22][23][31][32][33][34][35][36] A wide range of materials has been analysed (from gasoline up to residual oil, asphaltenes and lubricating oil), having various contents of Ni (<0.001-850 mg kg À1 ). Only a few studies were devoted to the analysis of oils of the cracking raw material type.…”

“…14 However, the simplest method of petroleum products analysis was direct analysis, using solid sampling accessories, 9,11,23 or aer dissolution in an organic solvent. 15,16,[19][20][21]35,36 The dissolution of crude oil in xylene (an efficient solvent for most petroleum products, also those containing asphaltenes) prior to GFAAS analysis was applied already in the work of Omang. 35 Since that time new facts have been discovered regarding the possible difficulties of GFAAS analysis of crude oil or its products.…”

“…To increase the thermal stability of the analyte before atomization, chemical modiers were applied. The most commonly used modier was Pd in the form of nitrate, [8][9][10]36 usually manually injected and thermally pre-reduced before a sample injection. In analyses with application of HNO 3 for emulsion or microemulsion formation, the acid itself could have worked as a modier by decomposition of volatile organic Ni compounds.…”