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1.
J. H. Zaidi M. Arif I. Fatima I. H. Qureshi 《Journal of Radioanalytical and Nuclear Chemistry》2002,253(3):459-464
Extensive use of pan, by one-tenth of world"s population, entails the evaluation of trace element contents in its ingredients. Radiochemical neutron activation analysis (RNAA) was developed and successfully employed to determine the concentration of 36 trace elements (essential, toxic and nonessential) in its four basic ingredients, leaf of betel pepper, betel nut, catechu and lime. The radiochemical separation methodology has significantly improved the detection limits of most of these elements due to suppression of Compton background. This study provides the base-line values of certain toxic and essential elements in these ingredients. The daily intake of essential and toxic elements through pan was estimated and compared with the recommended values. The cumulative intake of Mn is four times higher than the recommended value and that of toxic elements is well below the tolerance limits. 相似文献
2.
In order to determine trace lanthanoids in geological and cosmochemical samples, an analytical procedure for radiochemical neutron activation analysis (RNAA) was developed, where lanthanoids are radio-chemically purified through precipitations of hydroxides and fluorides, and cation exchange using HBr as an eluent. Chemical yields are determined by reactivation. The procedure was applied to the Allende meteorite and geological standard rocks. Our data for Allende are in excellent agreement with literature values, and those values for standard rocks, JP-1 (peridotite) and JF-2 (feldspar), in which lanthanoids are depleted by orders of 1 to 2 compared with those in Allende, seem to be reasonable, although not properly evaluated because of large scatterings in their literature data. This suggests that the present RNAA procedure is highly effective in determining trace lanthanoids (less than 1 ng) in rock samples. 相似文献
3.
J. H. Zaidi M. Arif I. Fatima S. Ahmed I. H. Qureshi 《Journal of Radioanalytical and Nuclear Chemistry》1999,241(1):123-127
Rapid radiochemical neutron activation analysis (RNAA) procedures were developed and employed for the determination of 32
trace impurities in high purity aluminum thin foils. Anion exchange column chromatography was developed for the sequential
group chemical separation of various elements which helped in reducing the spectral interferences and improving the sensitivity
of the method. The procedure is simple and requires a very short time to separate the elements in three groups for radiometric
assay. To determine very low contents of uranium and thorium,239Np and233Pa as activation products were separated using anion exchange and coprecipitation methods. The impurity contents were found
to be low, therefore, their adverse effects on microelectronic devices would be negligible. Our data could partially be compared
with the data reported in literature. 相似文献
4.
Fourteen elements can be rapidly determined in whole blood by the neutron activation analysis procedure described. Three of these (Ag, Cl, Se) are measured after a 10-s irradiation and eleven others (Al, Ba, Br, Ca, Cu, I, Mg, Mn, Mo, Rb, V) are determined by a 180-s irradiation of a 1-cm3 sample of whole blood after destruction of organic matter and removal of sodium by hydrated antimony pentoxide. A further 13 elements (As, Au, Co, Cr, Cs, Fe, Hg, K, Na, Ni, Sb, Sc, Zn) are determined after overnight irradiation in the SLOWPOKE reactor. 相似文献
5.
R. Caletka R. Hausbeck V. Krivan 《Journal of Radioanalytical and Nuclear Chemistry》1988,120(2):305-318
A radiochemical neutron activation technique for the detemination of 19 elements in high purity tungsten has been developed. It is based on extraction with diantipyrylmethane (for tantalum and antimony), substoichiometric extraction of molybdophosphate (for phosphorus) and anion-exchange chromatography (other elements) in hydrofluoric acid medium. The results obtained and achievable limits of detection are given. The effects of self-shielding and nuclear interfering reactions are discussed. 相似文献
6.
7.
A rapid and simple method has been developed for the determination of Mn, Zn, Cr and Ag by radiochemical thermal neutron activation analysis, involving solvent extraction and precipitation technique. Mn, Zn, Cr and Ag can be determined with an accuracy of 8.9, 5.8, 7.7 and 7.6%, respectively. The method has been employed for determination of the elements in fish solubles. Two samples and a standard can be analyzed in three hours. 相似文献
8.
V. A. Maihara M. Gallorini M. B. A. Vasconcellos 《Journal of Radioanalytical and Nuclear Chemistry》1995,198(2):343-348
A radiochemical separation procedure based on chromatographic separation using Chelex-100 in 0.1M HAc-0.1M NH4Ac at pH 4.8 and TDO in 6M HCl, has been developed to determine Cd, Co, Cr, Fe, Se, The, U, W and Zn in three biological materials of botanic origin used as SRM's: 1547 Peach Leaves, 1515 Apple Leaves and the new proposed material Spinach. The aim was to obtain more information for these elements whose values are not yet determined or are given only as suggested values. 相似文献
9.
R. Zeisler R. R. Greenberg S. F. Stone 《Journal of Radioanalytical and Nuclear Chemistry》1988,124(1):47-63
A comprehensive approach to the analysis of human livers was developed in a pilot program for the National Environmental Specimen Bank that employed a combination of four analytical techniques. Refinements in this approach were needed for improvement in detection limits, more effective sample usage and to reduce the number of analytical steps that were involved. Since neutron activation analysis (NAA) had determined most of the elements, expansion of NAA was chosen to achieve these goals. Modifications in the instrumental NAA procedures, including the use of a Compton Suppressor System, gave increased sensitivity for some low level elements, such as arsenic and chromium. Radiochemical procedures that followed the instrumental counts increased the sensitivity for the elements chromium, selenium, arsenic, molybdenum, silver, antimony, and tin. Results are given for two radiochemical procedures that were applied following the modified procedure, either the use of an inorganic ion exchange column or a liquid/liquid extraction, and these are compared to instrumental results. 相似文献
10.
M. Fedoroff C. Loos-neskovic G. Revel 《Journal of Radioanalytical and Nuclear Chemistry》1980,55(2):219-232
A systematic study of radiochemical separations of carbon in molten salts was achieved. It combined forecasting of salt mixtures
from literature data and experimental work The basic three mixtures of molten salts which were studied, are the following:
Pb3O4−B2O3, NaOH−NaNO3 and H2SO4−KIO4 with some additions of complexing agents Selected procedures for the determination of carbon by photon activation were issued
for the following samples: Ag, Al, Cr, Fe, Mg, Mo, Ni, Si, Ti, W, Zn, Zr, AlMg, AgZn and ZnMgTe. The detection limit for carbon
was 10−8 g and the accuracy from 5 to 10%. Applications to solid state science are given. 相似文献
11.
A simple two step radiochemical separation scheme has been developed which permits the RNAA determination of As, Cd, Cu and Mo in biological matrices. The RNAA separation is applied following the INAA determination of at least 17 other elements in the same samples. Under our experimental conditions which included a four day decay period for handling and shipping from a remote reactor site, detection limits for As, Cd, Cu and Mo are 0.24, 6.6, 45 and 3.4 ng, respectively, in NBS biological standard reference materials SRM 1571 and 1567. Decontamination factors for the major spectral interferences,82Br,42K,24Na32P and122Sb have been determined and found to be sufficiently high for measurement of the elements of interest in most biological matrices. The overall INNA/RNAA procedure takes full advantage of high resolution Ge(Li) gamma-ray spectroscopy and involves minimal chemical processing. 相似文献
12.
Gel filtration and neutron activation analysis methods were combined in work aimed at the development of methods for the determination
of metals firmly bound to protein in human blood serum. The values obtained are semiquantative. A purely instrumental technique
afforded data on Cu, Fe, Zn, Al and Mn but values for the latter two only were determined since Cu, Fe and Zn are already
well known. The concentrations for Al and Mn were found to be 300 ppb and 0.4 ppb, respectively. Despite the high resolution
of Ge(Li) detectors, no other metals were found. For the determination of any others, radiochemical separations are necessary
and were used to obtain data on the following elements: As 3 ppb, Ag 3 ppb, Au 0.003 ppb, Cr 1 ppb, Sb 1 ppb, Co, Cd, Mo and
Sn could not be detected and upper limits were estimated to be 0.1 ppb, 2 ppb, 2 ppb, and 1 ppb, respectively. 相似文献
13.
A review is given of the methods that have been proposed for enrichment of trace elements in samples that are to be analysed by neutron-activation methods. The emphasis is on classification of methods, with full illustrations by means of practical examples. 相似文献
14.
Summary Results for up to 12 trace elements in some newer biological materials of the NBS Washington (Citrus Leaves, New Bovine Liver, Wheat and Rice Flours, Milk Powder, Stabilized Wine) are reported using radiochemical neutron activation analysis. A discussion of the techniques and problems of standardization and the correct use of standards is included.
Presented in part at the 9th International Symposium on Microchemical Techniques, Amsterdam, August 1983. 相似文献
Radiochemische Neutronen-Aktivierungs-Analyse zur Standardisierung von Spurenelementen in biologischen Referenzproben in ng-Mengen
Zusammenfassung Ergebnisse für bis zu 12 Spurenelemente in einigen neuen biologischen Proben des NBS, Washington, (Citrus-Laub, frische Rindsleber, Weizenund Reismehl, Milchpulver, Wein) wurden mitgeteilt, die mittels radiochemischer Neutronen-Aktivierungs-Analyse erhalten wurden. Eine Diskussion der Verfahren, der Probleme der Standardisierung sowie der korrekten Verwendung der Standardproben wurde geboten.
Presented in part at the 9th International Symposium on Microchemical Techniques, Amsterdam, August 1983. 相似文献
15.
A radiochemical neutron activation analysis method, based on the separation of the radionuclides by anion-exchange from a 20 mol/l HF/3% H2O2 medium, was applied to the analysis of ultra-high purity molybdenum oxide and molybdenum metal and high-purity molybdenum silicide for 29 elements including the detrimental impurities Co, Cr, Fe, K, Na, Ni, Th, U and Zn. The achievable limits of detection for these elements are between 0.02 ng/g (for Co) and 50 ng/g (for K). The results were compared with those obtained by glow discharge mass spectrometry, inductively coupled plasma atomic emission and mass spectrometry, isotope dilution mass spectrometry and slurry sampling and direct solid sampling ETAAS. On the basis of the comparison of the results, the feasibility of the methods for analysis of these ultrapure materials is discussed.Dedicated to Professor Dr. Dieter Klockow on the occasion of his 60th birthday 相似文献
16.
Nguyen Van Suc 《Journal of Radioanalytical and Nuclear Chemistry》1994,187(1):67-71
A procedure for separation of Au, Ag, Pt, and Pd in geological samples has been developed. After irradiation, samples were fused with Na2O2 and silver was separated by filtering through a PbCl2 filter in 4M nitric acid solution. Au, Pt and Pd were concentrated with rhodium and thiourea as rhodium sulfide and the separation process of these elements was carried out by a chromatographic method. Au, Pt and Pd were retained on a Dowex-1×8 anion column in 1M HCl. Pd was eluted from the column by using a mixture of 75% HCl acid-25% acetone. Au was eluted by using a mixture of 10% HCl-90% acetone. In the gold fraction, Pt was also determined through the photopeak of199Au radionuclide (158 keV). The method was simple and rapid. 相似文献
17.
G. V. Iyengar 《Journal of Radioanalytical and Nuclear Chemistry》1987,110(2):503-517
A simple radiochemical machine incorporating ion-exchange procedures has been described. The system has been tested repeatedly for the determination of Cd, Co, Cr, Cu, Mn and Mo at ultra trace concentration levels in a variety of biological samples such as reference materials, human blood serum, human milk, hair and certain dietary materials, thereby demonstrating its suitability for practical use. The procedure can also yield results for A, Au and W, without any further chemical manipulations. Results show <1, 0.12, 0.18, 983, 0.61 and 0.91 g/l for Cd, Co, Cr, Cu, Mn and Mo, respectively, in human blood serum. Corresponding concentrations in human milk are <1, 0.25, <1, 186 to 310, 4 to 40 and 5.8 g/l. Among the reference materials, IAEA milk standard A-11 shows 1.85, 5.1, 17, 380, 260 and 101 ng/g for Cd, Co, Cr, Cu, Mn and Mo, respectively. Corresponding concentrations in animal muscle H-4 are 4.1, 5, 10.2, 4000, 455 and 45 ng/g. Importantly, this scheme has been applied to process large number of samples from single investigations such as those arising from dietary studies, obtaining quick and reliable data for routine use.In memory of Knut Samsahl, the devoted Norwegian radiochemist. 相似文献
18.
Twenty trace elements and heavy metals of Dalat lake sediment were analyzed by neutron-activation analysis at the ASTRAREACTOR. The elaborated method was also controlled by analyzing the reference material for lake sediment SL-1 of IAEA. It showed a good agreement with the certified values for most of the elements. The relative errors ranged from 1% to 25%. 相似文献
19.
The Rio Grande Reservoir, Southeast of the São Paulo Metropolitan Area, supplies water for four counties (about 1.6 million people). It has been seriously affected by urban expansion due to chaotic urban occupation and improper use of the surrounding areas. In this study bottom sediment samples were collected during the dry season and rainy season. Four sampling points were defined and located at the mouth of the Rio Grande and Ribeirão Pires Rivers (points 1 and 2), in the middle of the reservoir (point 3) and near the catchment point of the water supply (point 4). Samples were submitted to instrumental neutron activation analysis and some metals, trace and rare earth elements were determined. The methodology validation according to precision and accuracy was carried out by reference material analyses. The results obtained were compared to earth crust values and also with results already published in the literature. The enrichment factor in relation to earth crust values using Sc as reference element was calculated and a strong enrichment was found for the elements As, Br, Sb, Th, U and Zn. A strong anthropogenic influence was observed for some elements, mainly in the points located in the entrance of the reservoir that receives domestic and industrial effluents from the rivers that reach the reservoir. 相似文献
20.
Xiaolin Wang Dongyan Liu Yibei Fu 《Journal of Radioanalytical and Nuclear Chemistry》1995,199(2):151-158
The extraction behavior of perrhenate with crown ethers has been studied and methods for the separation and determination of rhenium have been developed. Perrhenate anion can be quantitatively extracted into nitrobenzene by benzo-15-crown-5 (B15C5) from 2M potassium hydroxide and back-extracted by sodium phosphate buffer solution. The molar ratio of B15C5 to KReO4 in the extracted species is probably 21. Rhenium was satisfactorily determined by neutron activation method in rock samples. 相似文献