Search Results
You are looking at 1 - 2 of 2 items for
- Author or Editor: R. Etwir x
- Refine by Access: All Content x
Abstract
We have determined the concentration of 25 trace elements in crude petroleum from seven Libyan oil fields by instrumental neutron activation analysis. Crude oil samples were irradiated with a thermal neutron dose rate of 1012 and 1013 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 Hg have a concentration range of 0.009 to 8747 ppb. The coefficients of variation are within 
10%. The elements V and Ni occur as both porphyrin and non-porphyrin and the ratio of these two forms varies 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.
Abstract
Medicinal herbs are often used as alternative medicines for healing and controlling some diseases in the world. This study focuses on the content of heavy and trace elements of some widely consumed herbs in Libya. Nine most popular herbs were analyzed by k 0-instrumental neutron activation analysis. All the samples, SRM and flux monitors were irradiated for 7 and 10 hours under thermal neutron flux of 1.3·1013 cm−2·s−1 at Tajoura nuclear reactor. In total, 33 elements were analyzed in different herbs. The variations in the concentration of the elements are attributed to soil composition and the climate in which the plant grows. The study showed that the toxic elements found in the samples were below the levels prescribed by health regulations. The precision and the accuracy of the results were evaluated by analyzing the reference materials Pine Needles SRM 1575 and Citrus Leaves SRM1572.
