NEUTRON-ACTIVATION ANALYSIS OF MAJOR AND TRACE-ELEMENTS IN CRUDE PETROLEUM

We have determined the concentration of 25 trace elements in crude pet roleum from seven Libyan oil fields by instrumental neutron activation analysis. Crude oil samples were irradiated with a thermal neutron do se rate of 10(12) and 10(13) n . cm(-2). s(-1) in the Tajoura research reactor. The concentration of U, Br, Mg, Cu, Na, V, Cl, Al, Mn and Ca is in a range of 0.015 to 84 ppm and that of sulphur of 0.12 to 1.8%. The elements Sc, Cr, Ni, Fe, Co, Zn, Ag, Se, Sb, Ba, Cs, Yb, Hf and H g have a concentration range of 0.009 to 8747 ppb. The coefficients of variation are within similar to 10%. The elements V and Ni occur as b oth porphyrin and non-porphyrin and the ratio of these two forms varie s over a wide range. The V/Ni ratios are located between 0.17 and 6.67 , which are comparable to the reported values for the crude oils from other countries.