Laser-induced breakdown spectroscopy measurements of uranium and thorium powders and uranium ore

Laser-induced breakdown spectroscopy (LIBS) was used to analyze depleted uranium and thorium oxide powders and uranium ore as a potential rapid in situ analysis technique in nuclear production facilities, environmental sampling, and in-field forensic applications. Material such as pressed pellets and metals, has been extensively studied using LIBS due to the high density of the material and more stable laser-induced plasma formation. Powders, on the other hand, are difficult to analyze using LIBS since ejection and removal of the powder occur in the laser interaction region. The capability of analyzing powders is important in allowing for rapid analysis of suspicious materials, environmental samples, or trace contamination on surfaces since it most closely represents field samples (soil, small particles, debris etc.). The rapid, in situ analysis of samples, including nuclear materials, also reduces costs in sample collection, transportation, sample preparation, and analysis time. Here we demonstrate the detection of actinides in oxide powders and within a uranium ore sample as both pressed pellets and powders on carbon adhesive discs for spectral comparison. The acquired LIBS spectra for both forms of the samples differ in overall intensity but yield a similar distribution of atomic emission spectral lines.     

Determination of uranium by XRF analysis following its preconcentration with some organic precipitants

The determination of uranium in natural waters by XRF analysis after its preconcentration with some organic precipitants is described.¹⁰⁹Cd source is used for the excitation of L-series X-rays of uranium. Separation yield, kinetics of coprecipitation and the possibility of preparing thin-layer samples for XRF analysis were studied in detail for uranium concentration with α-nitroso-β-naphtol, methylene blue with ammonium thiocyanate, tannin with urotropine and other precipitants. A procedure using coprecipitation of uranium with α-nitroso-β-naphtol from 500 ml samples of surface or waste, waters is proposed.     

超细样品的地质分析应用

采用X-射线荧光(XRF)、电感耦合等离子体光谱和质谱(ICP-AES/MS)技术,研究了超细地质分析样品(约800目)的分析方法和条件.结果表明,对于超细样品,XRF可直接粉末压片制样而不必高温熔融制样进行高精度的主、次组分测定;ICP-AES/MS的取样量可降至2 ～5 mg(仅为-200目样品的1/20 ～1/50),试剂用量大大减小,样品更易消解,不仅可节约成本,降低能耗,还显著减小了对环境的影响.讨论了发展超细样品分析的意义及对地质分析技术发展的可能影响.     

Simultaneous solvent extraction and high-performance liquid chromatographic determination of uranium, iron, nickel and copper in mineral ore samples and phosphate rock residues using N,N′-ethylenebis(salicylaldimine) as complexing reagent

The reagent N,N-ethylenebis(salicylaldimine) (H₂SA₂en) has been examined for precolumn derivatization, followed by solvent extraction in chloroform and HPLC determination of uranium, iron, nickel and copper on a Hypersil ODS 3 μm column. Complexes were eluted isocratically using a ternary mixture of methanol-acetonitrile-water and UV detection was at 260 nm. The detection limit was 12 ng/injection for each of the elements. The method has been applied for the determination of metals in mineral ore samples and phosphate rock residues. The results obtained are compared using atomic absorption.     

Application of Compton scattering normalization method to the analysis of uranium ore

Compton scattering normalization method is described for the analysis of uranium bearing ore respect to the usage of K X-rays of uranium. Minimum backscatter energy is obtained at a scatter angle of 180° with fixed point source geometry and collimation in appropriate conclusions. By normalizing the intensities of uranium K-lines to the Compton profile in the measured spectra, the results do not depend on several measuring parameters such as primary radiation intensity, matrix, composition, mass of the sample and measuring time. The method presented in this study indicates the convenience of uranium K-lines analysis for thick targets with an adequate measuring geometry.     

The homogeneity of heavy metal deposition on glass fibre filters collected using a high-volume sampler in the vicinity of an opencast chrome mine complex at Kemi,Northern Finland

The homogeneity of heavy metal (Cr, Ni, Cu, Fe and Cd) distribution on glass fibre filters (Munktell MG 160, 203 x 254 mm, 75 g m(-2)) collected using a high-volume sampler (Wedding & Associates) at an opencast chrome mine complex at Kemi, Northern Finland was studied. The heavy metals in the total suspended particulate (TSP) material were analysed by inductively coupled plasma atomic emission spectrometry (ICP-AES) or graphite furnace atomic absorption spectrometry (GFAAS). The glass fibre filters were digested in a microwave oven using a mixture of aqua regia+HF acids. There was significant non-uniform distribution of heavy metals on glass fibre filters. The TSP material containing chromite was very difficult to dissolve by acid digestion. The results from X-ray fluorescence spectrometry (XRF), and from energy filtering transmission electron microscope (EFTEM) equipped with energy dispersive X-ray spectrometer (EDS), showed that insoluble residue left after microwave oven digestion with aqua regia+HF acids was probably partly due to chemical reactions occurring during microwave heating.     

Liquid Cathode Glow Discharge as a Microplasma Excitation Source for Atomic Emission Spectrometry for the Determination of Trace Heavy Metals in Ore Samples

A novel liquid cathode glow discharge (LCGD) was designed as a microplasma excitation source for atomic emission spectrometry (AES) and used for the determination of Pb, Cu, and Cd in digested ore samples. The operating parameters and stability of LCGD-AES were investigated in detail. The statistical analysis (t-test) was used for comparing the results of ore samples using LCGD-AES and inductively coupled plasma atomic emission spectrometry (ICP-AES). The results showed that the optimized analytical conditions are 650?V discharge voltage, 4.5?mL?min^?1 solution flow rate, and pH 1 HNO₃ as the supporting electrolyte. The limits of detection for Pb, Cu, and Cd were 0.019, 0.47, and 0.37?mg?L^?1, respectively. The correlation coefficients and relative standard deviations were 0.9985 and 1.19% for Pb, 0.9868 and 2.37% for Cu, and 0.9960 and 3.98% for Cd. The power consumption was below 65?W. The recoveries were in the range from 79.1 to 115.1%. Moreover, the measurement results of ore samples by LCGD-AES are comparable to the values obtained by ICP-AES. Therefore, the LCGD-AES may be developed as a portable analytical instrument for the direct determination of trace heavy metals.     

青藏高原白刺、枸杞和沙棘果粉中微量元素含量比较研究

采用原子吸收光谱法、氢化物原子荧光光谱法对青藏高原白刺、枸杞、沙棘果粉中的13种元素进行了分析测定。结果表明,3种植物果粉中的Cu、Fe、Mn、Zn、K、Ca、Na、Mg等8种元素含量丰富且差异显著,Pb、As、Cr、Cd、Hg等5种重金属元素含量均较低,为3种植物资源深度开发利用提供了基础数据。     

Effect of air drying on speciation of heavy metals in flooded rice paddies

Flooded soil samples were collected in the typical area of the Yangtze Delta Region;fractions of heavy metals in flooded and air dried samples were measured with BCR sequential extraction method and atomic absorption spectrometry.In flooded soils, fractions of heavy metals increased in the order of acid soluble < oxidizable < reducible < residual.The acid soluble and reducible fractions significantly decreased but residual fraction significantly increased when the samples were air dried.The data obtained from air dried soil samples could not accurately represent the speciation of heavy metals in flooded field conditions.     

电感耦合等离子体原子发射光谱(ICP-AES)法测定岩矿中锂的含量

采用氢氟酸+高氯酸分解试样,硝酸浸取,电感耦合等离子体原子发射光谱法测定岩矿中的锂含量.锂测定范围0.10％ ～10.0％.通过不同混合酸溶样效果比较,仪器测定条件的优化、干扰元素的影响等实验,建立了一种电感耦合等离子体原子发射光谱(IC P-A ES)法测定岩矿中锂量的方法,完全能够满足岩矿中锂含量的检验工作.经加标...     

15种中成药中有害重金属铅、镉、铜含量的测定

为了解中药重金属污染情况,测定了市售常用15种中成药中重金属铅、镉、铜的含量,其中铅、镉采用石墨炉原子吸收法,铜采用火焰原子吸收法测定.结果表明,15种中成药均不同程度被这3种重金属污染,通心络中铅、镉、铜含量都已超标,桑菊感冒片镉超标,中药重金属污染问题仍然存在.     

Differentiation of Spanish brandies according to their metal content

Eleven metals, namely, aluminium, calcium, cadmium, copper, iron, lead, magnesium, manganese, potassium, sodium and zinc were determined in twenty samples of Sherry brandies and twelve samples of Penedés brandies by applying atomic spectrometry techniques. Flame atomic absorption spectrometry was used for quantitating calcium, copper, iron, magnesium, manganese and zinc; atomic emission spectrometry to determine potassium and sodium; and graphite furnace atomic absorption spectrometry to analyse aluminium, cadmium and lead. A chemometric approach was followed to study the discrimination between brandies from Sherry or Penedés according to the metal profile.     

Determination of lead concentration and film thickness in electroluminescent calcium sulfide thin films by X-ray fluorescence

Summary For the analysis of electroluminescent thin films, X-ray fluorescence (XRF) provides a convenient method as both the concentration of the dopant and the film thickness can be determined rapidly and non-destructively. An XRF method for the determination of thickness and lead concentration in lead doped calcium sulfide thin films was developed. Calibration standards made of polyvinyl alcohol and gelatin as well as filter paper standards were used. In addition, the applicability of a fundamental parameter program UniQuant was investigated. For comparison, the concentrations of lead and calcium were determined after dissolution by atomic absorption spectrometry. Generally, the correlation between the different methods excluding the use of filter paper standards was satisfactory. When the dopant concentration was very low or very high, however, the fundamental parameter program yielded best results. Determination of thicknesses by XRF was made by comparing the sulfur K intensities of the sample and those of a zinc sulfide standard. A correction factor for molar masses and densities was applied. The thicknesses obtained were compared to those measured with a profilometer after etching and the deviations were found to be less than 10%.Dedicated to Professor Dr. Wilhelm Fresenius on the occasion of his 80th birthday     

Iminodiacetic acid/ethylcellulose as a chelating ion exchanger : Part 1. Determination of trace metals by atomic absorption spectrometry and collection of uranium

A chelate-forming ion exchanger, iminodiacetic acid/ethylcellulose, is used for the separation of trace metals from waters and different organic solvents. Added uranium was collected from sea waters with recoveries of about 97%. Graphite-furnace atomic absorption spectrometry and solution spectrophotometry were used to quantify the metals. For the direct determination of trace metals in waters by the graphite-furnace method, a simple matrix-matching method is described. The detection limit for cadmium was 0.1 μg l^?1 and for lead 1 μg^?1 in drinking water.     

Stoichiometry determination of (Pb,La)(Zr,Ti)O3-type nano-crystalline ferroelectric ceramics by wavelength-dispersive X-ray fluorescence spectrometry

Analysis of small samples of lanthanum-doped lead zirconate titanate (PLZT) by wavelength-dispersive X-ray fluorescence spectrometry (WDXRF) is presented. The powdered material in ca. 30 mg was suspended in water and collected on the membrane filter. The pure oxide standards (PbO, La₂O₃, ZrO₂ and TiO₂) were used for calibration. The matrix effects were corrected using a theoretical influence coefficients algorithm for intermediate-thickness specimens. The results from XRF method were compared with the results from the inductively coupled plasma optical emission spectrometry (ICP-OES). Agreement between XRF and ICP-OES analysis was satisfactory and indicates the usefulness of XRF method for stoichiometry determination of PLZT.     

Characterization of foxing stains in early twentieth century photographic and paper materials

Abstract

The subject of this present work is a group of nine historical pictures shot in Palermo by the Sicilian photographer E. Interguglielmi in 1912. They are nine matte-collodion prints mounted on the original cardboard supports and all of them show foxing stains affecting the paper surface. In order to characterise the chemical composition of the supports and investigate foxing spots, non-destructive and micro-destructive analysis were carried out. X-rays fluorescence (XRF) analysis was used to characterise the elemental composition of all the mounting boards, allowing a comparison between the foxing spots and non-affected areas. Laser-Induced Breakdown Spectroscopy was used to investigate the presence of lower atomic number elements, not detectable by XRF, while SEM imaging allowed the investigation of surface appearance and nature of original paper samples from the cardboards.     

Uranium enrichment measurements using the intensity ratios of self-fluorescence X-rays to 92 keV gamma ray in UXKα spectral region

In this paper, the known multigroup γ-ray analysis method for uranium (MGAU) as one of the non-destructive γ-ray spectrometry methods has been applied to certified reference nuclear materials (depleted, natural and enriched uranium) containing ²³⁵U isotope in the range of 0.32-4.51% atom ²³⁵U. Its analysis gives incorrect results for the low component ²³⁵U in depleted and natural uranium samples where the build-up of the decay products begins to interfere with the analysis. The results reveal that the build-up of decay products seems to be significant and thus the algorithms for the presence of decay products should be improved to resulting in the correct enrichment value. For instance, for the case of ²³⁵U analysis in depleted uranium or natural ore samples, self-induced X-rays such as 94.6 keV and 98.4 keV lying in UXK_α spectral region used by MGAU can be excluded from the calculation. Because the significant increases have been observed in the intensities of uranium self-induced X-rays due to γ-ray emissions with above 100 keV energy arising from decay products of ²³⁸U and ²³⁵U and these parents. Instead, the use of calibration curve to be made between the intensity ratios of self-fluorescence X-rays to 92^* keV γ-ray and the certified ²³⁵U abundances is suggested for the determination of ²³⁵U when higher amounts of decay products are detected in the γ-ray spectrum acquired for the MGAU analysis.     

Health risks associated with the exposure to uranium and heavy metals through potable groundwater in Uttarakhand state of India

The present work aims to assess health risks associated with the exposure to uranium and heavy metals via potable groundwater in Uttarakhand state of India. For this purpose, potable groundwater samples were collected from the area and analyzed using LED fluorimetry and inductively coupled plasma mass spectrometry (ICPMS). The radiological (carcinogenic) and chemical (non-carcinogenic) risks associated with the exposure to uranium in majority of locations were observed below the safe limits suggested by WHO and USEPA. The levels of heavy metals present in potable groundwater were found well below the permissible limits recommended by WHO. An inter-comparison exercise between the results obtained with LED fluorimetry and ICPMS techniques was performed for the assurance of reliability and accuracy of results. The results were found in good agreement with each other.

     

广东地产中药中几种重金属元素的含量测定

通过火焰原子吸收分光光度法对十三种广东地产中药中锰、镍、锌、铜、铅和镉等重金属元素含量进行了测定 ,以初步了解广东地产中药的重金属含量情况     

Sorption of Cadmium from Aqueous Solutions at Different Temperatures by Mexican HEU-type Zeolite Rich Tuff

Many factors may affect the heavy metals sorption on natural zeolites among them the temperature, for this reason in this paper the cadmium retention behavior on Mexican zeolitic rich tuff as a function of temperature is considered. The kinetic and the isotherms were determined at 303, 318, and 333 K, the remaining cadmium in the solution samples was analyzed by atomic absorption spectrometry. The pseudo-second order rate constant, k, as well as the apparent diffusion coefficients were calculated from the cadmium uptake by the zeolitic rock as a function of the contact time and temperature, the highest amounts were found for the experiments done at 333 K. The maximum cadmium adsorption capacity by the zeolitic material was 12.2 mg Cd²⁺/g at 318 K corresponding to 20% of the effective ion exchange capacity of the Chihuahua zeolitic rock. In order to explain the cadmium sorption behavior different kinetics and isotherm models were considered.