Quantitative multielemental analysis of titaniferous magnetites

Two representative titaniferous magnetite samples procured from Moulabhanj, Orissa, India have been studied by PIXE, EDXRF, Mössbauer spectroscopy, and XRD techniques. Major iron-bearing phases identified in the samples by Mössbauer spectroscopy and XRD are magnetite, hematite, ferrous ilmenite and ferric ilmenite. The Fe²⁺/Fe³⁺ ratio and the relative percentages of different minerals were determined from the resonance areas of Mössbauer spectra. Quantitative multielemental analysis was carried out by energy dispersive X-ray fluorescence (EDXRF) and proton induced X-ray emission (PIXE). Nineteen minor and trace elements have been quantified by EDXRF whereas by PIXE eighteen elements have been analyzed quantitatively. Concentrations of trace elements determined by EDXRF and PIXE were used in interpreting the physico-chemical condition of the depositional basin.     

Quantitative X-ray fluorescence analysis of multielemental subjects of complex shape without implementation of reference standards

A theoretical dependence of the ratio of intensities of X-ray fluorescence lines of chemical elements on the ratio of their concentration in a sample is suggested. The effect of various experimental factors on parameters of the obtained model is considered. A method of quantitative X-ray fluorescence analysis of multielemental subjects using the suggested calibration dependence without the implementation of reference standards is described. The adequacy and analytical advantages of the developed approach are demonstrated for the determination of the elemental composition of a sample of a metal alloy of complex shape.     

A review on molybdenum determination in solid geological samples

This review highlights the necessity for the development of proper sampling and storage, fast pretreatment methodology followed by highly sensitive detection for the determination of molybdenum in geological samples. Distribution of concentration and chemical speciation of molybdenum analysis in solid geological matrices have also been discussed.     

Spectrographic determination of barium and strontium in geological samples

Ohne Zusammenfassung

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Polarographic determination of Tergitol 08

     

Application of energy dispersive X-ray fluorescence spectrometry as multielemental analysis to determine the elemental composition of crumb rubber samples

The elemental content of different rubber samples was analyzed using different analytical methods (inductively coupled atomic emission spectroscopy and non-polarized energy dispersive X-ray fluorescent spectroscopy). A new application of energy dispersive X-ray spectrometry as an analytical method for the determination of elemental content of rubber samples was investigated. Control analyses were also carried out to compare the results by ICP-AES. In one hand four samples contained same quality of elements (Mg, Si, P, S, Ca, Fe, Zn), while another four samples were without phosphorous. On the other hand there were significant differences in the ratio of C/H in the case of each sample. Based on the results, it was concluded that the X-ray spectrometry as an analytical method is well-applicable to determine the elemental composition of rubber samples, but the calibration is a key part of the analysis. A good correlation was observed between the different methods, but the correlation was the function of characteristic of matrices. Significant matrix effect from the presence of phosphor was observed in the case of some samples, while the change of C/H ratio could not result notable matrix effect.     

Rapid determination of gold in geological samples using flow injection solid-phase chemiluminescence.

The solid-phase chemiluminescence analysis of gold on the surface of an anion-exchange resin was studied. A method for the fast determination of gold using flow injection was established. The anion-exchange resin was used as an adsorbent of gold ion in the form of AuCl4-. The cation-exchange resin was used for the on-line separation of cations in the matrix. To obtain the best results, the preconcentration and separation conditions, chemiluminescence conditions, interfering ions and their elimination conditions were optimized. The linear range of the calibration curve of AuCl4- is from 0 microg ml(-1) to 5.00 microg ml(-1). The detection limit of AuCl4- is 0.012 microg ml(-1). The method has been used for the determination of gold in geological samples (standard ores). The results are in agreement with certified value of gold standard samples with relative standard deviation from 2.22% to 8.97%. Through the use of flow injection, the preconcentration and separation can be performed automatically.     

Quantitative GC determination of water in small samples

Summary A gas chromatographic method with thermal conductivity detector (TCD) was developed for the determination of water in small amounts (2mg–20 mg) of solid chemicals. Quantification of water is carried out by using ethanol as an internal standard. The method shows good linearity in the range 0.1%–10% water. The precision as repeatability tested with a sample containing 0.5% water has a coefficient of variation of 5.3%. Comparison of the GC test results with another independent method (Karl-Fischer-titration) confirms the accuracy of the new method. Easy handling, independence of the chemical structure of the test substance and the small amount of sample needed are the major advantages of this alternative method of determining the water content of solid chemicals.     

Quantitative analysis by X-ray photoelectron spectroscopy without reference samples

A comparison between X-ray fluorescence analysis (XRFA) and X-ray photoelectron spectroscopy (XPS) indicates the applicability of these two methods as relative and absolute techniques. For XPS the absolute field of application should be preferred. An improvement of the Hirokawa-Ebel method (an absolute XPS analysis) is presented in this paper. It is shown that the knowledge of the inelastic mean free paths of the photoelectrons (IMFP) is no longer required, but the energy dependence of the IMFPs can be used as a basis. This guarantees simplicity and much more universal applicability.     

Anion-exchange separation and spectrophotometric determination of thorium in geological samples

To determine thorium in geological samples it is first separated from all matrix elements by means of anion-exchange. After elution thorium is determined spectrophotometrically by using thoronol or arsenazo III. The suitability of the method for the determination of both trace and larger amounts of thorium was tested by analysing numerous geochemical standard samples with thorium contents in the range of 1-1000 ppm. In all cases very good agreement was obtained.     

Determination of the sulphur content of geological samples by X-ray fluorescent analysis

Summary The sulphur content of ultramafic and basic rocks is determined by X-ray fluorescent analysis with pressed powder pellets. A commonly marked cellulose powder and wax are taken as diluent. Two analysing crystals, PET and graphite, are compared. The linear calibration curve reaches from 50 ppm to 1.0 weight-%, with a detection limit of 90 and 45 ppm, respectively. If the standard rock is of nearly the same matrix as the examined samples, no calculated matrix correction is necessary.

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Schwefelbestimmung in geologischen Proben durch Röntgenfluorescenz-Analyse

Zusammenfassung Eine Methode zur röntgenfluorescenzanalytischen Schwefelbestimmung an ultrabasischen und basischen Gesteinen wird beschrieben. Die Messung erfolgt an Preßtabletten mit handelsüblichem Cellulosepulver oder Wachs als Verdünnungsmittel. Zwei Analysatorkristalle, PET und Graphit, werden verglichen. Die lineare Eichkurve umfaßt den Konzentrationsbereich zwischen 50 ppm und 1 Gew.-% S. Die Nachweisgrenze liegt bei 90 bzw. 45 ppm, je nach verwendetem Kristall. Bei annähernd übereinstimmender Matrix von Standard- und Analysenprobe ist eine rechnerische Matrixkorrektur nicht erforderlich.

     

X-ray fluorescence spectrometric determination of trace amounts of actinides on electrodeposited samples

A sensitive method is developed to determine traces of uranium, thorium and plutonium in effluent steams from nuclear fuel preparation and recycling facilities. Samples are prepared by electrodeposition of homogeneous, very thin actinide oxide layers on brass plates covered by a polished nickel surface. This procedure allows the aplication of α-spectrometric control measurements. Samples containing about 100 ng of actinide element are determined by x.r.f., which corresponds to actinide levels of 0.1 mg l^?1 in effluents under routine conditions. Simultaneous actinide determinations are possible. Fission products do not interfere.     

X射线荧光光谱法测定地质样品中的硫和氟

采用粉末压片制样-X射线荧光光谱法研究地质样品中硫(S)和氟(F)元素的快速测定方法。通过分级过筛实验优化确定样品粒度,探讨样品粒度对测定结果的影响,并进行实际样品和标准物质验证。结果显示,样品粒度为85μm时,经实际样品和标准物质验证,测定结果与化学值和标准认定值相符,且相对标准偏差(RSD)均小于2%。方法具有准确度高、检出限好、测试范围宽、简便快速等优点,能确保样品分析结果的准确性,实现了地质样品中S和F的快速测定。     

Selenium determination in biological samples by X-ray emission spectroscopy

Determination of Se in blood serum by PIXE and XRF is presented. Two different sample preparation methods combined with two modes of sample excitation are compared. Both methods are shown to be suitable for Se determination in blood serum and in standard reference materials (horse kidney IAEA H-8 and bovine liver NBS 1577a).     

Review of methods for the determination of lanthanides in geological samples

The following methods of determining lanthanides in geological samples are reviewed, together with the separation techniques necessarily associated with them: neutron-activation analysis, atomic-absorption and flame-emission spectrometry, plasma-source emission spectrometry, mass spectrometry, X-ray fluorescence spectrometry, and spectrophotometry.     

Quantitative analysis of X-ray absorption spectra using a 2D map representation

A promising possibility for the quantitative analysis of X-ray absorption near edge structure (XANES) spectra of nanosized electrode materials is demonstrated. We used a 2D map representation technique, which utilizes the values of the first derivatives of the absorbance with respect to the inserted Li(+) content plotted over the two-dimensional space defined by the inserted Li(+) content (mole) versus photon energy (eV) as a single map. The technique was applied to XANES spectra of the Li(y)CoO system in the first Li(+) insertion reaction for determining the structural and electronic variations associated with the change in Li(+) content. The obtained show that the intensities of two peaks at 7725 and 7711 eV increased with the Li(+) content and the difference of intensity change of these two peaks carried out for successive couples of spectra yielded the largest changes at 1.05 and 1.98 mol of Li content. This approach for quantitative analysis of XANES without using conventional simulation techniques enable us to interpret X-ray absorption spectroscopy (XAS) as a quantitative analytical technique with greater confidence.     

The determination of molybdenum in geological samples by Neutron Activation Analysis

A metal-silicate extraction technique combined with neutron activation analysis has been developed to determine molybdenum in geological samples. The samples are equilibrated with Femetal powder at high temperatures. Molybdenum is completely extracted into the metal phase because of very reducing conditions in the furnace. The metal spherule is separated from the silicates, irradiated and dissolved in an acid solution. The molybdenum is precipitated as a sulfide and the precipitate is dissolved in aqua regia and counted on a Ge/Li/detector. The radiochemical yield is obtained by irradiation of the solution. The method avoids production of⁹⁹Mo from induced fission of²³⁵U by performing the metal-silicate separation before irradiation. The precipitation step may be necessary to remove the high background from the decay of⁵⁹Fe. Mo concentrations down to 15 ng/g have been obtained using this method.     

An X-ray fluorescence method for gold determination in ore samples

A new method for gold determination in ore is presented. By the method called PREFIX (preconcentration and X-ray fluorescence), it is possible to detect trace concentrations of gold down to the level of 0.2 g/g, without any device.     

Quantitative characterization of bamboo cortex structure based on X-ray microtomography

Cellulose - Bamboo is a natural fiber composite with layered structure. Millions of years of evolution have endowed bamboo with the most effective structure in nature. The ingenious microstructure...     

Comparative methods for determination of rare earths in geological and mineral samples

Particle induced X-ray emission (PIXE) has been used for the quantitative analysis of rare earth elements (REE) in thick targets prepared from geological and mineral samples. Measurements were made with 1 and 3 MeV proton beams. For comparison, determination of the same elements was made by X-ray fluorescence (XRF) using a²⁴¹Am annular source. Minimal detectable limits (MDL) have been estimated for the two situations. Neutron activation analysis (NAA) has also been used for the determination of REE at the ppm level.