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 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 Egyptian molasses by instrumental neutron activation analysis

Multielement neutron activation analysis has been applied to the determination of macro, micro and trace amounts of Al, Br, Ca, Cl, Co, Cr, Cs, Fe, K, La, Mg, Mn, Na, Rb, Sc and V in molasses of Kom Ombo, Edfu, Armant, Naga Hammady and Abu Korkass cane sugar factories. The threshold element concentrations are acceptable and below the safety. Differences in element concentrations may be related to different botanic textures and structures, different compositions of sugar cane plants, corrosion of containers or changes in soil as a result of geochemical differentiation. The method is sensitive down to 0.038 ppm of V. The relative errors due to counting statistics are in the range of 0.2–11%.     

Determination of trace elements in Nigerian kola-nuts by instrumental neutron activation analysis

The trace elements content of Cola acuminata and three varieties of Cola nitida have been determined using neutron activation analysis. The samples have been irradiated at the Joint Universities Research Reactor, Risley, England for 7^1/2 hours in a neutron flux of 2.5·10¹² n·cm^–2s^–1 and analysed using high resolution lithium drifted germanium detector coupled to a Canberra 35 microprocessor as a 4096 channel gamma spectrometer. The elements: Na, K, Br, W, Fe, Cs, Co, Zn, and Sc were detected.     

Determination of major and trace elements in crude oils by neutron activation and reflection methods

The concentrations of O, Na, Cl, V, Mn and Ni in crude oils of different origins were determined, using sampling (SNAA) and on-stream (ONAA) activation analyses. Samples were irradiated with thermal and fast neutrons produced by a 0.3 mg²⁵²Cf source and a 14 MeV generator. The H-content and the C/H atomic ratio have been determined by thermal neutron reflection method using an 18 GBq Pu−Be source. This work was supported in part by the Hungarian Academy of Sciences.     

Determination of toxic and trace elements in algae by instrumental neutron activation analysis

Instrumental neutron activation analysis has been applied in the determination of toxic and other trace elements in a set of three algae materials provided by the International Atomic Energy Agency, with the aim of environmental preservation through enhanced applications of nuclear analytical techniques. The quality of the analysis method has been evaluated by analyzing a number of biological standard reference materials. By adding mineral nutrients, the cultivation of algae for metals is enhanced, in particular, selected toxic heavy metals such as As, Cd, Cr, Hg, Ni and Pb. It is believed that the level of elemental concentration in algae samples are dependent on environmental conditions due to its biochemical properties. Therefore, algae materials may be useful as an indicator or controller of environmental water pollution.     

Multi-element analysis of Ghanaian crude oils by instrumental neutron activation analysis

Instrumental neutron activation analysis based on thermal neutrons from the Ghana Research Reactor-1 facility was utilized to analyze 18 trace elements namely Al, As, Br, Ca, Cd, Cl, Co, Cu, Fe, K, Mg, Mn, Na, Ni, S, Si, V, and Zn in two different crude oil samples from the Saltpond and Jubilee field in the Saltpond, Central region and Cape Three Points, Western region of Ghana, respectively. The sulfur concentration for both samples were low and within globally accepted range of 0.1–0.5%wt for sweet crude oil. The results of the elemental analysis showed that the two samples are relatively low in trace element concentrations compared to crude oils of other countries. Higher Fe concentration in the Jubilee crude oil indicates younger oil. The V/Ni ratios obtained for crude oils from both locations imply a possible marine organic origin and also suggest the Saltpond crude oil is more matured than the Jubilee crude oil.     

Determination of trace elements in carbonate reference samples by instrumental neutron activation analysis

Twenty elements (Sm, U, As, Sb, La, Ce, Yb, Th, Cr, Eu, Hf, Ba, Cs, Tb, Sc, Rb, Fe, Zn, Ta, Co) have been determined by instrumental neutron activation analysis in GSJ/AIST carbonate reference samples, JCp-1 (Coral) and JCt-1 (Giant Clam), together with JLk-1 (Lake Sediment), JDo-1 (Dolomite) and JLs-1 (Limestone) reference samples.     

Determination of trace elements in sugar cane refuse by instrumental neutron activation analysis

Multielemental instrumental neutron activation analysis has been utilized for the determination of micro, trace and ultratrace amounts of Al, As, Au, Br, Ca, Cl, Co, Cr, F, Fe, K, La, Lu, Mg, Mn, Na, Sc, V and W in sugar cane refuses of Armant, Kom Ombo, Edfu, Deshna and Naga Hammady Factories. The element concentrations are below the safety baseline levels. Variations of results may be related to different botanic structures, different compositions of sugar cane plants or ecologic changes in soil. The method is accurate and precise. The relative errors are in the range of 0.3–12.3%.     

Determination of trace elements in atmospheric wet precipitation by instrumental neutron activation analysis

Instrumental neutron activation analysis (INAA) methods have been developed for the simultaneous determination of multielement concentrations in both particulate and soluble fractions of atmospheric wet precipitation (AWP). Samples of AWP collected across Canada by Canadian Network for Sampling Precipitation (CANSAP) have been analyzed. The INAA method involves four sequential irradiations and counting after five different decay periods for measuring Ag, Al, As, Au, Ba, Br, Ca, Ce, Cl, Co, Cr, Cu, Dy, Fe, Hf, Hg, I, K, La, Mg, Mn, Na, Rb, Sb, Sc, Se, Sm, Sr, Ti V and Zn. Precision and accuracy of the INAA methods have been evaluated, and detection limits have been calculated.     

Determination of trace elements in Chinese medicinal plants by instrumental neutron activation analysis

Roots of Astragalus membranaceus, Angelica sinensis, Glycyrrhiza uralensis and Codonopsis pilosula, which were often used as herbs in traditional Chinese medicine, were analyzed by Instrumental Neutron Activation Analysis (INAA). The samples were collected in Gansu, northwest of China and irradiated at the 15 MW heavy water reactor in China Institute of Atomic Energy (CIAE). The induced activities were counted by a well calibrated low background γ-spectrometer equipped with a high efficiency coaxial high-purity germanium (HPGe) detector. The concentrations of eighteen trace elements (Ca, Fe, Na, Zn, Ba, Rb, Ce, Cr, La, Co, Th, Cs, Sb, Sc, Sm, Hf, Eu and Tb) in the herbs were determined. Possible links between pharmacological action of the herbs and content of some elements were also discussed in this paper. The measured results were compared with the reported values in literature.     

Determination of trace elements in biological materials by instrumental epithermal neutron activation analysis

The use of reactor epithermal neutrons in instrumental activation analysis is described for the determination of trace elements via long-lived isotopes. A boron carbide filter is used. Results of analyses of human erythrocytes, plasma, urine and some biological reference materials are given to demonstrate the applicability of the method to biological samples. Bromine, iron, cesium, rubidium, selenium and zinc and cobalt are determined. The method provides accuracy and reliability similar to conventional thermal neutron activation but is faster. Limits of detection attainable with the two techniques are compared.     

Determination of lanthanides and other trace elements in ferns by instrumental neutron activation analysis

About 70 kinds of fem samples have been analyzed by means of neutron activation analysis in order to deduce characteristics and mechanisms of accumulation of rare earth elements. Accumulator species for scandium and lanthanides have been newly found based on the analysis. Correlations among barium, hafnium, and lanthanides indicate that the fems accumulating barium and hafnium also showed high concentrations of lanthanides. Remarkable accumulation of lanthanides in diversifying genera suggests that lanthanides contribute to making those species diverse.     

Determination of 34 elements in Chinese geochemical standard reference materials by instrumental neutron activation analysis

Thirty four elements (Al, As, Ba, Br, Ca, Ce, Co, Cr, Cs, Dy, Eu, Fe, Gd, Hf, Ho, K, La, Lu, Mg, Mn, Na, Nd, Rb, Sb, Sc, Sm, Ta, Tb, Th, Ti, U, V, W, Yb) were determined by instrumental neutron activation analysis in the second set of Chinese geochemical standard reference materials (sediments from GSD-9 to GSD-12, soils from GSS-1 to GSS-8, rocks from GSR-1 to GSR-6) using both thermal and epithermal irradiations. Irradiation schemes designed to utilise short, medium and long-lived nuclides were employed in order to analyse major, minor and trace elements with different half-lives. The gamma-ray spectra were measured by Ge(Li) and HP(Ge) detectors. Relevant nuclear data and possible interferences are listed, and analytical results are presented and discussed.     

Determination of trace elements in some Nigerian vegetable based oils by neutron activation analysis

The concentrations of some essential micronutrient elements leadingto short-lived activation products in four Nigerian vegetable based oils (palmoil, palm kernel oil, sheabutter and groundnut oil) have been determined byneutron activation analysis using a small research reactor. One sample ofeach material was analysed and presented as an introduction for further investigations.Results indicate that the concentration range of the elements are 19.4–44.0µg/g for Al; 30.0–81.0 µg/g for Ca; 11.9–60.4 µg/gfor Cl; 1.43–5.96 µg/g for Cu; 7.3–28.1 µg/g for Mg;0.47–1.69 µg/g for Mn; 17.5–72.8 µg/g for Na and 0.04–0.07µg/g for V. The experimental procedure is suitable for routine determinationof micronutrient element in foods for control and monitoring purposes.     

Determination of rare earth elements in fern leaves using instrumental neutron activation analysis

The lanthanides (REE) in 142 fern leaves collected from several sampling sites in Japan have been determined by neutron activation analysis, and the correlations between any two REEs in the logarithmic scattering diagram were examined. The relationship was expressed by the general formula, Y=aX+b with a correlation coefficient R. A strong positive correlation was seen between any two REEs in the diagram with a regression coefficient and a correlation coefficient close to unity. However, between Eu or Tb and other REEs the relationship was split into two lines with the same correlation coefficient. From the intercept b, the relative abundance of the two elements was determined for each REE and compared with those in hickory and tobacco leaves. These findings indicated that the abundance pattern of fern leaves is quite different from those of hickory and tobacco leaves. Namely, the relative abundance of La and Ce was quite similar in the three plants, but the abundance of the other REEs (Nd, Sm, Gd, Dy and Lu) was considerably lower in ferns than in hickory and tobacco leaves. For Eu and Tb the higher values obtained in fern leaves coincided with those of the two plants.     

Characterization of trace elements in medicinal herbs by instrumental neutron activation analysis

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.     

Preconcentration and instrumental neutron activation analysis of acid rain for trace elements

A combination of instrumental and preconcentration neutron activation analysis (NAA) methods has been developed for multielement determination in acid rain. Concentrations of 24 elements have been measured in the particulate matter of rainwater by the instrumental NAA method which involves 3 irradiation and 4 counting periods. Trace elements in the soluble fraction of rainwater have been preconcentrated using Chelex-100 resin. Various factors that could influence the retention of elements on to the resin have been examined, and reagent and other blanks investigated in detail. Concentrations of 15 elements have been measured by directly irradiating the resins. A graphite furnace atomic absorption spectrometry method has been used for determining Cd and Pb levels in the soluble fraction. Precision and accuracy of the methods have been evaluated, and limits of detection and determination calculated. The methods have been applied to rainwater samples collected from 36 locations across Canada. Enrichment factors, interelement and inter-ion concentration correlation coefficients are discussed     

Determination of trace elements in human brain tissues using neutron activation analysis

Neutron activation analysis was applied to assess trace element concentrations in brain tissues from normal (n = 21) and demented individuals (n = 21) of both genders aged more than 50 years. Concentrations of the elements Br, Fe, K, Na, Rb, Se and Zn were determined. Comparisons were made between the results obtained for the hippocampus and frontal cortex tissues, as well as, those obtained in brains of normal and demented individuals. Certified reference materials, NIST 1566b Oyster Tissue and NIST 1577b Bovine Liver were analyzed for quality of the analytical results.     

Determination of trace elements in soil and plants in the Orontes basin of Syria by using instrumental neutron activation analysis

Instrumental neutron activation analysis (INAA) have been used for the determination of some major, minor and trace elements (As, Cr, Co, Ni, Zn, Sb, Sc, Ce, Ti, Fe, Mn and V) in various plant leaves together with their soil. The accuracy of the measurements have been evaluated by analyzing a number of plant and soil reference materials, precision have been estimated by triplicate analysis of the sample as well as that of the reference material. The obtained accurate and reliable data of some trace elements on microgram level for plants and soil will serve as baseline values and will be helpful to monitor the changes in the trace element content of soil and plant leaves.The authors are thankful to Prof. I. Othman General Director of AECS for his encouragement and his support.