Simultaneous multielement determination of rare earth elements by substoichiometric activation analysis

This paper presents simultaneous substoichiometric separation of four rare earth elements; samarium, europium, terbium and ytterbium. The elements are separated simultaneously and substoichiometrically by forming their complexanates with substoichiometric DTPA and extracting their unreacted parts with HTTA. Application to the determination of these elements by substoichiometric neutron activation is also presented.     

Use of CRM's as mutual calibrating materials and control of syntheti multielement standards as used in INAA

The comparability of analytical results from different laboratories requires accurately known concentrations in the applied standards. Dilution effects of different multielement synthetic standard solutions have been studied by measuring 10–12 different concentrations of the same solution. Peak area comparison of four Certified Reference Materials (CRM's) using one value for the evaluation of the other three repetitively led to the intercomparison (degree of compatibility) of the certified values. The idea of the preparation of each laboratory's secondary reference standard by comparison of synthetic multielement standards with as many CRM's as practically feasible is advocated to improve the reliability of analytical results.     

Simultaneous multielement determination in microliter samples by rapid-scanning spectrometry coupled to a microwave-induced plasma

A modified electrothermal atomizer is coupled to a helium microwave-induced plasma (m.i.p.) for atomic emission spectrometry. For preliminary evaluation, this arrangement was coupled to a monochromator to quantify single elements in microliter samples. Detection limits range from 3 to 25 pg for Cd, Fe, Pb, Mn and Au and linear dynamic ranges are 2–4 orders of magnitude. The monochromator, fitted with a rapid scanning galvanometer mirror, is also used as a multielement detector. A spectral window of ca. 40 nm is rapidly scanned (10 Hz) across the exit slit and five elements from one solution are determined in rapid sequence. In the multielement mode, the detection limits are in the range 50–250 pg, as might be expected, owing to the decreased duty cycle. However, there is a significant improvement when compared to an earlier report from this laboratory. By narrowing the spectral coverage and taking data more rapidly this drawback is minimized.     

Multielement determination in Tillandsia by INAA

Instrumental neutron activation analysis was employed to measure 43 elements, including some macroconstituents, in the leaves of some species of the epiphytic genusTillandsia (Bromeliaceae). The results, confirming the oligotrophyc nature of the genus, are briefly discussed with regard to a possible role as multielemental environmental monitors.     

Halogen speciation in the rat thyroid: Simultaneous determination of bromine and iodine by short-term INAA

The study describes a mode of non-destructive simultaneous determination of bromine and iodine concentrations, by reactor instrumental neutron activation analysis (INAA) in the regime of short-term activation. Under the conditions of 1-minute activation in the neutron flux of 8.0·10¹³ n·cm⁻²·s⁻¹, it was possible to determine reliably as little as 5·10⁻⁸ g bromine and about 10⁻⁷ g iodine in matrices of a given type and of the mass of about 5 mg dry weight. We applied this method for the determination of Br and I concentrations in the whole rat thyroid gland as well as for the halogen speciation in fractions separated from this organ.     

Simultaneous determination of hafnium and zirconium in low grade uranium ores using INAA

A non-destructive neutron activation analysis technique has been developed for the determination of hafnium and zirconium in low grade uranium ores. In order to calculate the fission contribution of²³⁵U, thermal neutron absorption cross-section /_a/ for⁹⁴Zr has been determined. The study shows that 1 g of uranium produces the same activity as from 10.03 g of zirconium. Based on this fact, the degree of interferences have been calculated for each sample and the necessary corrections have been applied. The values have been compared with the reported IAEA and NBS values.     

Trace quantities of uranium in some Indian chewing tobaccos as determined by fission track analysis

The sandwiched pellet technique using Makrofol-E plastic track detectors has been employed to determine trace quantities of uranium in nine brands of flavored chewing tobaccos consumed by the Indian population. In this technique the nuclear reaction,²³⁵U(n,f), is used for the quantitative estimation of uranium. The maximum value of uranium (1.88 ppm) has been found in raw tobacco leaves (Surti), while the minimum (0.13 ppm) in Tulsi (Double Zero brand). Other seven brands showed intermediate values of U-contents which are also reported in this paper. These values are compared with the U-contents reported in the literature for other forms of tobaccos.     

Simultaneous determination of short-to-medium lived nuclides in Ghanaian food items using INAA and Compton suppression counting

Summary An instrumental neutron activation analysis (INAA) method was developed for the simultaneous determination of 19 elements in 10 individual food items from Ghana. The samples were irradiated for 1 minutes in a neutron flux of 2.5.     

Trace element impurity determination in aspirin tablets by INAA

Instrumental neutron activation analysis (INAA) was applied to assess trace element concentrations in six samples of aspirin tablets acquired in São Paulo city, Brazil. Concentrations of the elements Br, Ca, Co, Cr, Fe, K, La, Na, Sc and Zn were determined. Comparisons were made between the results obtained with published data for aspirins from foreign countries. Certified reference materials, INCT-MPH-2 Mixed Polish Herbs were analyzed for quality control of the analytical results.     

Simultaneous multielement atomic-absorption analysis of biological materials

A prototype multielement atomic-absorption spectrometer (SIMAAC) consisting of a continuum source and an echelle polychromator modified for wavelength modulation, has been used to determine several elements in a variety of biological materials. Analyses have been done with flame atomization as well as graphite furnace atomization. Compromise atomization conditions do not significantly limit the accuracy or precision. Analytical results for a variety of samples are reported.     

The determination of trace elements in active charcoal by INAA

Neutron activation followed by X-ray spectrometry with magnetic deflection of -rays was applied to the nondestructive determination of Co, Cu and Br in active charcoal.     

Simultaneous determination of lead, nickel, tin and copper in aluminium-base alloys using slurry sampling by electrical discharge and multielement ETAAS

The simultaneous multielement determination of Pb, Sn, Ni and Cu in aluminium alloys by electrothermal atomic absorption spectrometry (ETAAS) was performed by a quick method using slurry sampling. The metallic colloidal slurries were obtained by an electrical discharge operated in liquid medium. In this work, the effects of aluminium were evaluated and the results show that it causes a strong retention of Pb, Ni and Cu at low pyrolysis temperatures which is overcome by employing high pyrolysis temperatures. Aluminium also significantly improves the thermal stabilisation of Pb and Sn, it being possible to reach pyrolysis temperatures of 1100 and 1300 °C, respectively. Such stabilisation indicates that the performance of aluminium as a matrix modifier for Pb is better than that obtained using phosphate and magnesium nitrate without substantial changes of the figures of merit. The effects of aluminium on the atomisation characteristics of the elements and those coming from the simultaneous multielement determination on the figures of merit of the elements are also discussed. In this work, a calibration procedure involving a matrix matching method with aqueous aluminium standards is proposed as a simple and efficient way to solve the inconveniences originated by the aluminium matrix. The proposed method was applied to the simultaneous multielement determination of several aluminium-base alloy standards giving results well within the recommended values.     

INAA of some phosphates used in fertilizer industries

INAA method for As, Br, Ca, Ce, Co, Cr, Eu, Fe, K, La, Lu, Na, Nd, Sb, Sc, Sm, Tb, Th, U, Yb and Zn determination in raw phosphates and Romanian NPK phosphate fertilizers was applied. The concentration values of uranium and some possible toxic elements in fertilizers are discussed.     

气相色谱质谱法同时测定建筑用胶中苯系物和邻苯二甲酸酯类增塑剂

建立了建筑用胶中苯系物和邻苯二甲酸酯类增塑剂等10种物质同时测定的气相色谱质谱法,对提取方法及色谱条件进行了研究,各物质的检出限在0.2～0.8 mg/L之间。在两个添加水平下,水基型和溶剂型建筑用胶中苯系物及邻苯二甲酸酯类增塑剂的回收率在98.1%～101.5%之间。5个实验室间对相同建筑用胶样品测定的相对标准偏差在1.9%～3.9%之间。     

Simultaneous multielement analysis of various human tissues by inductively-coupled plasma atomic-emission spectrometry

Human soft tissues were analysed by inductively-coupled plasma atomic-emission spectrometry (ICP-AES) for twelve elements. The tissues had been vacuum-dried for storage and were dry-ashed at low temperature and then digested with nitric acid prior to analysis. Accuracy and precision were examined by analysing NBS Standard Reference Material 1577 Bovine Liver. For P, K, Na, Mg, Ca, Fe, Cu, Zn and Cd, the concentrations obtained were within 4% of the certified or informational values. It was found that cerebrum, cerebellum, heart, kidney, liver, pancreas, spleen and muscle samples in portions of less than 1 g dry weight could be conveniently analysed for these elements.     

Simultaneous multielement analysis of zeolite catalysts by inductively-coupled plasma atomic emission spectrometry

Summary A method comprising digestion of zeolites with an acid mixture followed by inductively-coupled plasma atomic emission spectrometry (ICP-AES) has been established for the simultaneous determination of Al, Na, La and Si in various zeolite samples. Various aspects including sample digestion, instrumental interference effects as well as analytical performance and applicability of the established method have been investigated in detail. The results indicated that aqua regia in combination with hydrofluoric acid was effective for decomposition of a wide variety of zeolite samples. The effects of borate and fluoride ions in the digested sample solution on the ICP-AES determination have been carefully investigated. The method established will be generally applicable for the simultaneous determination of Al, Na, La and Si in zeolite with a precision of 5%. The analytical results obtained were checked by comparison with classical wet chemistry methods and found to be in reasonably good agreement. Application to the kinetic study of La-NaY exchange reaction was also performed.

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Simultane Multielementanalyse von Zeolit-Katalysatoren durch ICP-AES

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Dedicated to Prof. Dr. W. Fresenius on the occasion of his 75th birthday     

双道氢化物发生-原子荧光光谱法同时测定核电用钢中痕量砷和锑

建立了双道氢化物发生-原子荧光光谱法同时测定核电用钢中痕量砷和锑的新方法。用王水溶解样品,以2.0 g/L L-半胱氨酸溶液作为预还原剂,在低酸度条件下实现对砷、锑的预还原。用20 g/L硼氢化钾溶液作为还原剂,氢化物发生反应在0.5 mol/L乙酸介质中进行。砷、锑的质量浓度在40μg/L范围与相应的荧光强度呈线性关系,方法的检出限(3s/k)分别为0.032μg/L和0.022μg/L。应用此方法同时测定了核电用钢及不锈钢标准样品中的砷锑含量,并与电感耦合等离子体原子发射光谱法的分析结果作了对比,测定值与标准样品的标准值相符,结果的相对标准偏差(n=8)均小于5.0%。     

Test of multielement analysis of bone samples using instrumental neutron activation analysis (INAA) and anti-Compton spectrometry

INAA and anti-Compton spectrometry has been employed in the analysis of test bone samples. Validity and accuracy of the method were checked by the use of two biological reference materials procured from the National Institute of Standards and Technology, USA (NIST) and the International Atomic Energy Agency, Austria (IAEA). NIST 1486 Bone Meal (ca. 200–800 mg) and A-11 Milk Powder (ca. 200–600 mg) samples were irradiated in the 100 kW TRIGA Mainz reactor. Concentrations of 13 elements in both biological reference materials have been determined and were found in good agreement with the certified and provisional values.     

Validation of methods for the determination of aluminium in fish gills by INAA and ICP-MS

In a European study of fish death in mixing zones of rivers with different acidities a reliable determination of Al and other elements in gills from freshwater fish was required, and both INAA and ICP-MS were studied as candidate reference methods. INAA requires minimum sample handling with a correspondingly small risk of contamination and no blank value; however, a careful study was needed of both nuclear interference from P and the increased detection limit caused by other major elements in the sample, before reliable results for Al could be ascertained. ICP-MS requires dissolution of the sample with a resulting risk of contamination and a significant reagent blank; while sensitivity was good, the interference from N created problems for sample decomposition in the microwave oven. Our experience with actual samples indicates that both methods suffer from considerable contamination problems, requiring that samples be handled in a clean bench with superpure reagents. Nuclear interference was determined experimentally by irradiating stoichiometric P-compounds with and without a Cd-shield; the observed interference of 1 g Al from 50 mg of P was found to require no correction in almost all cases. The accuracy of results was ascertained by analyzing SRM 1577 Bovine Liver.     

Simultaneous multielement detection in particle beam/hollow cathode-optical emission spectroscopy

Presented here is the development of a particle beam/hollow cathode-optical emission spectroscopy source that has been interfaced with a high resolution polychromator for use as a species-specific detector for chromatographic separations. Use of the high resolution JY RF-5000 polychromator allows simultaneous, multielement analysis; a necessary requirement for comprehensive speciation analysis. Parametric optimization was performed for the nebulization conditions, desolvation temperature, glow discharge current and pressure, and the source block temperature (vaporization) using nitrate salts containing lead, nickel, and silver. Peak area, height, and width were recorded for optical emission of Pb (I) 220.35 nm, Ni (I) 341.41 nm, and Ag (I) 338.28 nm in order to determine optimal peak characteristics under chromatographic separation conditions. Response curves for a multielement salt solution containing Pb, Ni, and Ag were obtained using the optimized conditions, with detection limits for triplicate injections of 2.2, 0.17, and 0.19 ng, respectively. The ability to monitor multiple elements simultaneously reveals the existence of interelement matrix effects that have not been noted previously in hollow cathode devices. The ability to monitor metals and non-metals is demonstrated towards the future application of this system as a tool for metallomic studies.