Determination of trace elements in petroleum by neutron activation analysis

Instrumental neutron activation analysis (INAA) and Ge(Li) spectrometry have been used to determine Sc, Cr, Fe, Co, Ni, Zn, As, Se, Sb, Eu, Au, Hg, and U in crude petroleum. The technique involves no chemical separations and no pre-concentration of the samples by ashing is necessary, thus avoiding contamination or loss of volatile elements. The estimated detection limits in ppb for the elements are Sc (0.1), Cr (0.16), Fe (400.0), Co (0.6), Ni (1.1), Zn (200.0), As (6.0), Se (23.0), Sb (1.0), Eu (0.58), Au (0.11), Hg (4.3), U (1.5). Precision values ranged from 0.1% to 15% (relative standard deviation). Interferences in the Co and Fe determinations due to fast neutron reactions (n, p) and (n, α) on Ni isotopes are small and are easily corrected. Losses of As, Se, and Hg due to escape of volatile gases during irradiation are negligible     

Determination of trace elements in petroleum by neutron activation analysis

Using thermal neutron activation and a large-volume high-resolution Ge(Li) γ-ray spectrometer, the feasibility of the determination of the concentrations of Na, S, Cl, K, Ca, V, Mn, Cu, Ga, and Br in crude oils has been demonstrated. This instrumental method, which requires neither a chemical separation technique nor pre-concentration or post-concentration of trace elements by ashing, eliminates many inherent errors associated with chemical determination. The method is sensitive, precise and suitable for routine analysis. Fast neutron (n, p) and (n, α) reactions do not appreciably interfere and where necessary corrections may be applied. Loss of volatile elements, e.g. chlorine and bromine, due to recoil during irradiation is negligible.     

Determination of 17 trace elements in gallium arsenide by reactor neutron activation analysis

A method has been developed for the simultaneous determination of 17 trace elements in gallium arsenide. The method involves reactor neutron irradiation of the samples, distillation of the arsenic matrix activity and Ge(Li) γ-ray spectrometry. For a sample size of 0.1 g and a 10-day irradiation at 2·10¹³ n cm^-2 s^-1, the detection limits vary from 70 p.p.b. (tin) down to 5·10^-3 p.p.b. (scandium).     

Determination of trace elements in water by non-destructive neutron activation

A systematic study was undertaken in order to find out which of the most relevant elements can be determined in water under normal conditions by non-destructive neutron activation simultaneously using a suitable monostandard method. Standardized water samples as well as natural water of different kind were used, brought to dryness by freeze-drying and irradiated in quartz at a neutron flux of 10¹⁴ cm⁻² s⁻¹ for 1 day. The trace element content in quartz ampoules of different origin was determined separately. The following elements are discussed in detail including possible interferences: As, Au, Br, Ca, Cd, Co, Cr, Cu, Eu, Fe, Hg, K, La, Mo, Na, Ni, Sb, Sc, Se, U, Zn. Presented at the Euroanalysis II Conference, Budapest, 25–30. Aug. 1975.     

Determination of trace elements in food by neutron activation analysis

Neutron activation analysis (NAA) methods have been developed for the determination of major, minor and trace elements in duplicate diets and individual food items. These include a cyclic instrumental NAA (CINAA) method for measuring Se content through its short-lived nuclide^77mSe; epithermal INAA (EINAA) for I and As; conventional INAA for Br, Ca, Cl, Co, Cr, Fe, K, Mg, Mn, Na, Rb, Sb, Sc, Sn and Zn; combination of EINAA and INAA for Al; radiochemical NAA (RNAA) for As, Au, Co, Cu, Fe, Hg, Mo, Sb, Se and Zn; and preconcentration NAA (PNAA) for U and Th. Accuracy of measurements have been evaluated by analyzing a number of biological and diet reference materials. Multielement concentrations of diets and foods have been measured by these methods.     

Determination of trace elements in a medicinal plant by neutron activation analysis

The concentration of inorganic elements in medicinal plants may be related to the concentration of active constituents. Instrumental neutron activation analysis has been employed to determine the elements antimony, cesium, chlorine, cobalt, iron, manganese, nickel, potassium, rubidium, selenium, sodium and zinc in different parts of Helleborus cyclophyllus BOISS. and in the soil in which the plant was grown. It has been found that antimony has a selective accumulation in the rhizome of this plant where the active constituents are located, as well as chlorine in petioles and leaves.     

Determination of trace elements in cardiotonic drugs by neutron activation analysis

Potassium may be intimately involved to the action of cardiac glycosides. Chlorine and potassium also act as diuretics. The elements chlorine, manganese, potassium and sodium are determined by instrumental neutron activation analysis in all the cardiotonic drugs which are currently used in Greece. All the available pharmaceutical forms of these drugs were analysed (pills, injections, water solutions). It has been found that there is a wide variation among the different values for managanese, sodium and chlorine while for potassium values are relatively constant. Results are discussed from the pharmacological point of view. It is proposed to study the role of manganese in cardiotonic drugs as well as the effect of potassium addition in oral pharmaceutical form of cardiotonic drugs in decreasing the toxicity of cardiac glycosides.     

Determination of trace elements in fish by instrumental neutron activation analysis

Instrumental neutron activation analysis, INAA, was utilized for the determination of Al, Au, Br, Ca, Cl, Co, Cr, Cu, Fe, I, K, Mg, Mn, Na, Rb, Sc, V and W in 12 Tilapia Nilotica samples collected from the Aswan High Dam Lake following the destructive techniques.     

Determination of trace elements in tea leaves by neutron activation analysis

Instrumental neutron activation analysis has been employed to determine 14 trace elements in two brands of Iranian and foreign tea. The elements are: Br, La, Ba, K, Mn, Cl, Cr, Cs, Rb, Fe, Co, Zn, Sc and Au. The transference ratio of the elements into solution, when tea is leached by percolation, is also reported. It was found that some elements are totally transferred into solution and some are partially retained by the leaves.     

Determination of trace elements in surface water by neutron activation analysis

In order to assure the public health, simple and relibable analytical methods must be established for effective surveillance of polluted surface water. Since the pollutants in surface water are usually found at ultratrace levels, preconcentration is generally required to ensure the quality of the analytical results. An analytical procedure consisting of preconcentration using hydrous magnesium oxide followed by neutron activation analysis has been proposed and applied to the determinations of trace elements in surface water.     

Determination of trace elements in biological material by neutron activation analysis

Eighteen trace elements in biological material [grass /Imperata cylindrica/, mimosa plant /Mimosa pudica/, rice] by neutron activation method were determined. In the comparative analysis, we found the content of the same elements was different in the each material, although they were collected at the same place and the same sampling method was applied.     

Determination of trace elements in marine organisms by neutron activation analysis

The content of Na, Sc, Cr, Fe, Co, Zn, As, Br, Sb, Cs, La, Ce, Sm, Eu, Lu and Hf inEunicella cavolinii, Cladocoro cespitosa, Cystoseira barbata, Zostera marina, Posidonia oceanica andUlva lactuca was found to be approximately 3–5 orders of magnitude higher than reported for sea water, as determined by nondestructive neutron activation analysis (NNAA). The relative amounts of these elements in all organisms investigated are very similar and reflect their ratio in the media. Rare earth elements, however, are an exception and their accumulation appears to be specific. Among the organisms investigated,Zostera marina has the highest capacity for accumulation of most elements determined and thus may be used as an “indicator” organisms.     

Determination of trace elements in chewing gum by neutron activation analysis

Six trace elements of nutritional or toxicological interest (aluminium, calcium, chlorine, manganese, sodium and strontium) have been determined in three different brands of chewing gum by instrumental neutron activation analysis. Unlike graphite furnace atomic absorption, neutron activation requires essentially no treatment of the gum sample prior to analysis. As a result, most of these elements may be quantitated in only a few minutes. For the particular brands of gum examined, none of the detected elements was found to be present at a level representing a substantial contribution to the total dietary intake of the element for an American adult.     

Determination of trace elements in beach asphalts by neutron activation analysis

The feasibility of using trace multielement data obtained from neutron activation analysis to identify the source of crude oil residues was recently demonstrated. This paper presents the concentrations of Br, Co, Cr, Sb, Sc, Zn, and V/Ni, for 30 crude oil residues collected from beaches (beach asphalt), using 1 g samples. The method does not require chemical separation or post-irradiation concentration. The average standard deviation for the V/Ni ratio was ±0.39.     

Determination of trace elements in carbonates by instrumental neutron activation analysis

A systematic non-destructive determination of eighteen trace elements (F, Na, Cl, Sc, Mn, Zn, Br, Sr, I, Ba, La, Ce, Sm, Eu, Tb, Yb, Th and U) in carbonate samples by thermal neutron activation analysis was developed. Three 0.2–0.5g samples were irradiated for 15 sec (in the case of determination of F), for 3 min (in the case of Na, Cl, Mn, Sr and I) and for 60 hrs (in the case of Sc, Zn, Br, Ba, La, Ce, Sm, Eu, Tb, Yb, Th and U) in the TRIGA MARK II Reactor at a thermal neutron flux of 5·10¹¹ n·cm⁻²·sec⁻¹ (15 sec and 3 min irradiation) and 1.5·10¹²n·cm⁻²·sec⁻¹ (60 hrs irradiation), respectively. According to the half life of the nuclides formed, the activities were measured with a Ge(Li) spectrometer as follows,²⁰F∶15 sec counting after 20–25 sec cooling,²⁴Na,³⁸Cl,⁵⁶Mn,^87mSr and¹²⁸I∶600 sec couting after 30–120 min cooling,⁸²Br,¹⁴⁰La,¹⁵³Sm,¹⁷⁵Yb and²³⁹Np (daughter of²³⁹U)∶3000 sec counting after 1 week cooling,⁴⁶Sc,⁶⁵Zn,¹³¹Ba,¹⁴¹Ce,¹⁵²Eu,¹⁶⁰Tb and²³³Pa (daughter of²³³Th)∶5000 sec counting after 1 month cooling. The errors due to the fluctuation of the neutron flux and the counting geometry were minimized by the use of calcium determined previously with EDTA-titration as an internal standard. The interferences from²⁴Mg(n, p)²⁴Na and²³⁵U(n, fission) reactions were corrected by the activities produced by the reactions in unit weight of magnesium and uranium, and their concentrations in samples measured experimentally. The data of Na, Mn, Zn and Sr were compared with the results obtained by atomic absorption analysis.     

Determination of trace elements in biological materials by neutron activation and extraction with TOPO

Solvent extraction with TOPO from 6M hydrochloric acid is proposed as a method for the elimination of interfering activities in neutron activation analysis of biological material for trace elements. By this procedure²⁴Na,⁴²K,³²P,⁸²Br, and⁴⁷Ca are efficiently removed, and a number of trace element activities can be measured by Ge(Li) spectrometry. Chemical yields are determined by re-activation. Data for Cu, Zn, Mo, and Cd in two biological standards are presented.     

Determination of trace elements of egyptian crops by neutron activation analysis

Neutron activation analysis, NAA, a high resolution Ge(Li) gamma ray spectrometer was used to determine the concentration of Al, As, Au, Br, Ca, Cd, Co, Cr, Cu, Fe, La, Mn, Mo, Sb, Se, W, and Zn in Cumin, coriander, carrots, and Daucus carrota (Umbelliferae Family), alfalfa, Kidney bean, Phaseolus sativus, Phaseolus vulgaris, bean, lenses, and fenugreek (Legumirosae Family). Multielement determination technique on destructive and nondestructive samples was followed. This method is simple, precise and sensitive to 17 trace elements.