Mössbauer Study of El-Bahrain Meteorite

Procedures for the determination of traces of rare earth elements (REE) in geological samples by instrumental neutron activation analysis (INAA) and high resolution liquid chromatography (HPLC) are presented. The international standard reference materials AGV-1, GSP-1 and G-2 (USGS) were tested for the determination of REE concentrations using both techniques. The results obtained showed good agreement with certified values, giving relative errors less than 10%. By using INAA, the REE La, Ce, Nd, Sm, Eu, Tb, Yb and Lu were determined. All the REE, except Dy and Y, were determined when HPLC was employed. The application of INAA and HPLC to the determination of REE in geological samples is also discussed.     

Determination of rare earth elements in sediment cores from Northern Saronikos Gulf,Greece, by instrumental neutron activation analysis

Instrumental Neutron Activation Analysis (INAA) has been applied for the determination of 8 rare earth elements (REE) in sediment cores collected from stations of polluted and unpolluted areas of Northern Saronikos Gulf. The REE determined in cores are: La, Ce, Sm, Eu, Tb, Dy, Yb and Lu. Higher levels of all REE were found in the cores from polluted areas of N. Saronikos Gulf as compared with those from unpolluted areas. Different vertical profiles of REE were found in the cores from two stations of polluted areas which indicate that REE may distinguish pollution sources.     

INAA determination of holmium in submilligram samples of cosmochemical and geochemical interest and the second-order activation interference

Second-order neutron activation becomes a serious interference in NAA determinations of REE in submilligram samples of meteoritic and terrestrial materials when neutron fluences reach levels of 10²⁰ n·cm^–2 or more. The Dy-interference to Ho determination and the Eu-interference to Gd determination are quite, large. We discuss the importance of second-order activation interferences in REE determinations, and present an experimental method to correct the Dy-interference to Ho determination by INAA. Ho concentrations in splits of less than 0.2 mg of BCR-1 and SP can be accurately determined by INAA with a neutron fluence of 2·10²⁰ n·cm^–2 in spite of large Dy interferences of up to 200%. It is necessary for NAA determinations of REE with high neutron fluences that each REE standard be separated from its neighboring REE, in order to correct the second-order activation interferences experimentally.     

Instrumental neutron activation analysis of carbonatites from Panda Hill and Oldoinyo-Lengai, Tanzania

Twenty nine (major and trace) elements including nine rare earth elements (REE) in African carbonatite samples were determined by instrumental neutron activation analysis (INAA). The geochemical behavior of trace elements in carbonatites, especially REE pattern (chondrite normalized), and the efficiency of neutron activation analysis compared to other methods are discussed in this study.     

Neutron activation analysis of the rare earth elements in rocks from the earth's upper mantle and deep crust

Three techniques for analyzing rare earth elements (REE) in geological materials are described, i.e. instrumental neutron activation analysis (INAA), neutron activation analysis with pre-irradiation chemical REE separation (PCS-NAA) and radiochemical neutron activation analysis (RNAA). The knowledge of REE concentrations in eclogites, peridotites and minerals from the earth's lower crust and upper mantle is very useful in constraining their petrogenetic history.     

Rare-earth elements abundance and distribution in pelagic sediments by instrumental neutron activation analysis

The geochemical behavior of REE has been tested in the Umbro-Marchean (Italy) pelagic sequences of Cretaceous-Paleocene age. REE were determined by INAA in a number of limestone, marl and clay samples. Both chondrite and shale normalized patterns are discussed: the observed REE amounts and distributions are mainly attributed to highly complex diagenetic processes.     

Rare earth element concentrations in mature and developing leaves of fern, Blechnacea, collected in the University Forests of Ashiu, Kyoto University

We have investigated the concentrations of REEs in fern leaves collected indifferently to the fern species from 9 sampling sites in Japan using INAA. The results indicated a large variation in the values obtained between fern leaves. In the present investigation we applied the same analytical method on the samples (Blechnaceae, a kind of fern, mature and developing leaves were collected from the same plant) restrictively gathered from the University Forests in Ashiu, Kyoto University. It was demonstrated that the variations in the REE concentrations decreased by one to two order of magnitude, and that the REE contents in developing leaves were also one to two orders of magnitude lower than those in mature leaves. It can be considered that fern accumulates REEs with their growth stages.     

Instrumental neutron activation analysis of some rock samples from Akwana and Arufu areas,Middle Benue Trough,Nigeria

Twenty nine (29) major, minor and trace elements including rare earth elements (REEs) were determined by INAA in rock samples from Akwana and Arufu areas, Middle Benue Trough, Nigeria. The rock units are located within the lead-fluorite and baryte mineralisation there. The concentrations of the major elements in the tertiary basalt (TB) and dolerite are similar while the elemental abundance in the granite gnesses is completely different. The elemental concentrations in the rock samples do not show any known relationship with fluorite abundance. The concentrations of some elements in both tertiary basalt and dolerite show them to be derived from alkali basaltic liquid. The chondritic normalised REE distribution patterns for the TB are similar to those of BCR-1 but the chondritic relative REE abundance is more enriched in TB than in the BCR-1. The chondritic normalised REE distribution patterns for the granite gneisses are also compared to those of the standard granite samples.     

REE bound proteins in natural plant fernDicranopteris dichitoma by MAA

Biochemical techniques, including pH variation, outsalting, ultracentrifugation, gel filtration chromatography and electrophoresis, etc., have been employed together with instrumental neutron activation analysis (INAA) to study the rare earth elements (REE) bound proteins in the natural plant fern,Dicranopteris dichitoma. INAA was also used to identify whether the proteins were bound firmly with REE. The results obtained show that two REE bound proteins (RBP-I and RBP-II) have been separated. The molecular weight of RBP-I on Sephadex G-200 gel column is about 8·10⁵ Daltons and that of RBP-II is less than 12,400 Daltons, respectively. However, SDS-PAGE of the two proteins shows that they mainly have two protein subunits with MW 14,100 and 38,700 Daltons. They are probably conjugated proteins, glycoproteins with different glyco-units.     

Determination of rare earth elements by neutron activation analysis in altered ultramafic rocks from the Akwatia District of the Birim diamondiferous field,Ghana

Summary Rare earth element (REE) analysis using instrumental neutron activation (INAA) was carried out on ultramafic rocks from the Akwatia District of the Birim diamondiferous field, Ghana, with the primary objective of investigating their kimberlitic characteristics. The total REE concentrations range from 113 to 1610 ppm and fall within the interval of those reported in the literature for kimberlites. Despite the marked difference in the REE contents, all the analyzed samples show similar REE patterns that resemble those of kimberlites. However, compared to most of the kimberlites, the ultramafic rocks have small negative Eu anomalies and low light-REE/heavy-REE ratios, suggesting that the rocks have been significantly assimilated by crustal rocks.     

Determination of rare earth elements in carbonatites from the Kangankunde Mine, Malawi by instrumental neutron activation analysis

Nine rare earth elements (REEs) in African carbonatite samples were determined by instrumental neutron activation analysis (INAA). The geochemical behavior of REEs in carbonatites, especially REE pattern (chondrite-normalized), is studied in relation to carbonatite formation at the Kangankunde Mine, Malawi. REE-rich phosphate minerals, particularly monazite, and the other unusual minerals such as strontianite, are observed during the stages of carbonatite formation. Four kinds of carbonatites exhibit similar chondrite-normalized REE distribution patterns in spite of the marked difference of their REE contents. All these carbonatites are characterized by the strong fractionation between light and heavy REEs and by the very high La/Yb ratio (1000-2800).     

Rare earth element patterns in ultramafic rocks of the Schist Belt of Southwestern Nigeria by instrumental neutron activation analysis

24 Ultramafic rock samples from 3 different areas of the Schist Belt of Southwestern Nigeria were analyzed for 11 rare earth elements (REE) by instrumental neutron activation analysis (INAA). REE patterns of the ultramafic rocks are similar for the 3 different areas, and the REE abundances are smaller than for other types of rocks from the same areas. However, the moderate fractionation between LREE and HREE observed for these samples is unusual for ultramafic rocks. Some geochemical implications of the results are discussed.     

Determination of rare earth and other trace element abundances in human kidney stones and brain tissue by instrumental neutron activation analysis

We have used INAA to analyze more than 30 minor and trace elements in 10 human kidney stones (phosphate and oxalate types). In addition we also analyzed human brain tissue samples for trace elements by INAA to determine the limitations of the method. Samples were taken from the temporal and frontal cortex of the brain of a patient that suffered from dialysis encephalopathy (where an increased Al content is expected), as well as a number of control samples. Trace elements were analyzed to study possible compositional differences other than the Al content. The analyses were done using large volume HPGe detectors; because of the low abundances, accuracy and precision vary between 3–80% for individual elements. We found a difference between the rare earth element (REE) patterns for apatite and oxalate kidney stones, and a fractionation compared to typical REE contents in plants. For the brain samples there is evidence for differences between the dialysis patient and the control samples not only for Al, but also for some other elements including the REEs, but most differences are minimal, and may not be significant.     

Single-crystal trace element analysis in rock-forming minerals by instrumental neutron activation analysis

We have developed an INAA techniques for analyzing single crystals extracted from rocks. Trace element contents have been measured in a large variety of mineral species, as well as isotopic ratios of some REE in minerals related to natural fission reactions. The sensitivity of INAA allows to avoid the main shortcomings of usual mineral geochemistry: (1) only very short quantities of minerals are needed (down to a few g), so that even very sparse minerals could be analyzed, (2) purity of minerals is carefully checked, and (3) the heterogeneity of a population may be studied. The method is especially useful when applied to minerals acting as tracers for some element families, e.g. REE in Ca-bearing minerals (fluorite, apatite, titanite, gamet) and Zr-bearing minerals, or chalcophile elements (Co, Ni, As, Sb, Mo, Ag, Au and Se) in sulfides. We present an application of the method to the Oklo U deposit in Gabon showing that features outlined above are of special interest for the study of hydrothermal processes.     

A comparison of INAA and ICP-MS/ICP-AES methods for the analysis of meteorite samples

Instrumental neutron activation analysis (INAA), inductively coupled plasma atomic emission spectrometry (ICP-AES) and ICP mass spectrometry (ICP-MS) (hereafter, ICPs) were applied to meteorite samples for the determination of elemental content. The analytical applicability and suitability of the three methods have been compared. Those comparisons led to the refinement of our analytical procedures for INAA and ICPs, yielding more reliable data. Our INAA data proved to be reliable enough for classifying meteorites, while the ICPs, especially ICP-MS, can characterize elemental abundance features in detail, as demonstrated by REE abundance patterns for the Allende meteorite. In this manner, INAA and ICPs can be used in a complementary fashion in cosmochemical studies.     

Determination of rare earth elements impurities in high purity uranium

A sensitive radiochemical procedure has been developed for the separation and determination of Dy, Sm, Gd, Eu, La and Lu in high purity uranium. The method is based on quantitative extraction of uranium using NPy/benzene as an extractant from 7M HCl solution. Rare earth elements (REE) remaining in the aqueous phase were subsequently determined by INAA.     

A contribution to the certification of some elements in eight vegetal reference materials by using instrumental neutron activation analysis

Instrumental neutron activation analysis (INAA) has been applied to the determination of 21 elements in 8 different vegetal samples, to be used as reference materials in 35 European laboratories (CII). Many of these elements hitherto have not been evaluated; they can be useful markers in many environmental problems. The INAA values are compared with CII non-nuclear analytical techniques results. Some rare earths elements (REE) have been also determined and their chondritic ratio versus atomic radius is reported.     

Rare earth element (REE) in surface mangrove sediment by instrumental neutron activation analysis

A study is carried out on the concentrations of rare earth element (REE) elements present in surface mangrove sediments from 10 locations throughout west coast Malaysia. In carrying out the analysis, the best and most convenient method being the instrumental neutron activation analysis (INAA). Samples were obtained, dried, crushed to powdery form and samples prepared for INAA. All the samples for analysis were weighted approximately 150 mg for short irradiation and 200 mg for long irradiation time. As calibration and quality control procedures, blank samples, standard reference material SL-1 were then irradiated with thermal neutron flux of 4 × 10¹² cm^?2 s^?1 at the MINT TRIGA Mark II research reactor which operated at 750 kW by using a pneumatic transport facility. The REE elements of surface sediment samples in this study are Dy, Sm, Eu,Yb, Lu, Tb, La and Ce. It was found that the level of concentrations of all the REE elements varies in the range (0.35–117.4 mg/kg). The geochemical behavior of REEs in surface sediments and normalized pattern (chondrite and shale) has been studied. The degree of sediments contaminations were computed using an enrichment factor. The results showed that the enrichment factor varied in the range (0.75–6.75).     

The non-destructive determination of REE in fossilized bone using synchrotron radiation induced K-line X-ray microfluorescence analysis

The sensitivity and applicability of the synchrotron radiation induced X-ray microfluorescence (μ-SRXRF) spectrometer at the Hamburg synchrotron laboratory Hasylab for the determination of the distribution of trace concentrations of rare-earth elements (REE) in fossilized bone are discussed and critically compared to those of other trace analytical methods such as instrumental neutron activation analysis (INAA) and LAMP-ICPMS (laser ablation microprobe inductively-coupled plasma mass spectrometry). Measurements were carried out on two bone samples from contrasting terrestrial depositional environments at Olduvai Gorge (Tanzania). Results indicate that the microdistribution of the REE in these biological materials is not homogeneous and that the relative abundance of these elements can provide information on the palaeoenvironment during the fossilization process. The heterogeneous distribution of the REE can be determined in a quantitative and completely non-destructive manner provided the concentrations of individual REE are above 10 μg/g.     

Multielement analysis by sequential instrumental and radiochemical neutron activation

We measured 37 elements in six USGS geological camples and one NBS biological orchard leaf (OL) sample, using sequential INAA and radiochemical group separation coupled with high resolution, high efficiency Ge(Li), and a Ge(Li) with anticoincidence shields. The elemental concentrations in these samples vary over three orders of magnitude. Our results agree very well with the reported values. The rare earth values in PCC-1 are 2–4 times lower than the reported values. Precise REE patterns are defined in USGS samples, which are characteristic of the total rock types. The REE pattern in OL is identical to the mineral apatite. In addition to the possibility that OL may be contaminated by local soil, it is also possible that the uptake of REE trace elements by plants from soil is perhaps dominated by accessory mineral such as apatite, or plants take up the REE from bulk soil in a preferential manner as a smooth function of the REE ionic radii.