共查询到20条相似文献,搜索用时 0 毫秒
1.
The homogeneity of IAEA RM SM-M-2/TM Marine Sediment was tested by INAA. The sampling constants a and b have been determined for 6 elements. 相似文献
2.
Daina Riekstina Vera Skvortsova Olgerts Veveris 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(3):1907-1911
The paper presents investigations of changes in optical absorption and photo luminescence spectra of magnesium oxide, and natural and synthetic magnesium aluminium spinel related with the content of transition metal ions (Cr, Fe, Mn) and the irradiation with fast neutrons. Six synthetic single magnesium aluminium spinel crystals with different stoichiometry (MgO·nAl2O3), five natural crystals from Ural and Pamir deposits, and seven MgO crystals were studied. Micro impurities (Cr, Fe, and Mn) and macro component (Mg, Al) quantities have been determined using the instrumental neutron activation analysis technique. Concentrations of impurities in different spinels were found in following ranges: for Cr—1 × 10?4 to 8 × 10?2 %, for Mn—2 × 10?5 to 23 %, for Fe—1 × 10?4 to 1.2 %. Three ranges of luminescence: 380–460, 650–850 and 850–1,050 nm, were established in the most part of the investigated MgO samples. Analysis shows that the intensity of emission in each of these regions is strongly dependent on the concentration of transition metal ions. Great deviation from the stoichiometry of the irradiated MgO·2.8Al2O3 crystal leads to the local structure of α-Al2O3 formation around Cr3+ ions. The orange emission is attributed to Mn2+ in octahedral coordination, it can be assumed that the band at 570 nm is belonging to the complex centre “Mn2+–F+ (or F centre)”. 相似文献
3.
4.
J. O. Santos C. S. Munita M. E. G. Valério C. Vergne P. M. S. Oliveira 《Journal of Radioanalytical and Nuclear Chemistry》2008,278(1):185-190
Instrumental neutron activation analysis (INAA), have been used for the definition of compositional groups of potteries from Justino site, Brazil, according to the chemical similarities of ceramic paste. The outliers were identified by means of robust Mahalanobis distance. The temper effect in the ceramic paste was studied by means of modified Mahalanobis filter. The results were interpreted by means of cluster, principal components, and discriminant analyses. This work provides contributions for the reconstruction of the prehistory of baixo São Francisco region, and for the reconstitution of the Brazilian Northeast ceramist population of general frame. 相似文献
5.
Elvis J. De França Elisabete A. De Nadai Fernandes Márcio A. Bacchi Peter Bode Rob T. M. van Soldt 《Journal of Radioanalytical and Nuclear Chemistry》2009,282(1):125-132
For environmental quality assessment, INAA has been applied for determining chemical elements in small (200 mg) and large
(200 g) samples of leaves from 200 trees. By applying the Ingamells’ constant, the expected percent standard deviation was
estimated in 0.9–2.2% for 200 mg samples. Otherwise, for composite samples (200 g), expected standard deviation varied from
0.5 to 10% in spite of analytical uncertainties ranging from 2 to 30%. Results thereby suggested the expression of the degree
of representativeness as a source of uncertainty, contributing for increasing of the reliability of environmental studies
mainly in the case of composite samples. 相似文献
6.
M. Michalska-Kacymirow E. Kurek A. Smolis M. Wierzbicka E. Bulska 《Analytical and bioanalytical chemistry》2014,406(15):3717-3722
The aim of this study was to evaluate the biological and chemical response of Allium cepa L. exposed to inorganic selenium compounds. Besides the investigation of the total content of selenium as well as its chemical speciation, the Allium test was used to evaluate the growth of onion roots and mitotic activity in the roots’ meristem. The total content of selenium was determined by inductively coupled plasma mass spectrometry (ICP MS). High-performance liquid chromatography (HPLC), coupled to ICP MS, was used for the selenium chemical speciation. Results indicated that A. cepa plants are able to biotransform inorganic selenium compounds into their organic derivatives, e.g., Se-methylselenocysteine from the Se(IV) inorganic precursor. Although the differences in the biotransformation of selenium are due mainly to the oxidation state of selenium, the experiment has also shown a fine effect of counter ions (H+, Na+, NH4 +) on the response of plants and on the specific metabolism of selenium. Figure
? 相似文献
7.
Simple, selective yet sensitive methods to quantify low-abundance bacterial biomarkers derived from complex samples are required in clinical, biological, and environmental applications. In this report, a new strategy to integrate sample pretreatment with chemical analysis is investigated using on-line preconcentration with chemical derivatization by CE and UV detection. Single-step enantioselective analysis of muramic acid (MA) and diaminopimelic acid (DAP) was achieved by CE via sample enrichment by dynamic pH junction with ortho-phthalaldehyde/N-acetyl-L-cysteine labeling directly in-capillary. The optimized method resulted in up to a 100-fold enhancement in concentration sensitivity compared to conventional off-line derivatization procedures. The method was also applied toward the detection of micromolar levels of MA and DAP excreted in the extracellular medium of Escherichia coli bacterial cell cultures. On-line preconcentration with chemical derivatization by CE represents a unique approach for conducting rapid, sensitive, and high-throughput analyses of other classes of amino acid and amino sugar metabolites with reduced sample handling, where the capillary functions simultaneously as a concentrator, microreactor, and chiral selector. 相似文献
8.
T. Martínez F. Aguilar J. Lartigue M. Navarrete L. A. Cuapio C. López O. Y. Morales 《Journal of Radioanalytical and Nuclear Chemistry》2008,278(2):365-370
Due to large consumption of tobacco in Mexico and in order to complement previous work performed by total reflection X-ray
fluorescence, the present study has determined 15 elements by INAA in 9 cigarettes brands being marketed in Mexico. As a part
of a Quality Control Program, NIST standard reference materials (SRM) and an IAEA reference material were analyzed to confirm
the accuracy and reproducibility. Average of As and Cd were 0.56 and 1.15 μg·g−1, respectively, in the range of those of foreign brands. 相似文献
9.
V. Kilikoglou P. Grimanis M. Vassilaki-Grimani A. P. Grimanis 《Journal of Radioanalytical and Nuclear Chemistry》1991,152(2):469-477
Two different instrumental neutron activation analysis (INAA) methods were applied to characterize chemically 74 ceramic roof tile samples, found in the town of Pella, Greece and dated back to the Hellenistic Period (3rd century B. C.). The samples were first analyzed for 17 elements with a 4 hour irradiation and two counts and then re-analyzed for 9 elements with a 1 minute irradiation and two counts of short-lived radioisotopes. The results of both methods were very similar, showing the validity of the rapid INAA method (1 min irradiation) in the study of ancient ceramics. All samples were divided into 4 chemical groups, each one representing a different tiling. 相似文献
10.
Rapid sample digestion by fusion and chemical separation of Hf for isotopic analysis by MC-ICPMS 总被引:1,自引:0,他引:1
A new method for rapid sample digestion and efficient chemical separation of Hf and REE from rock samples for precise isotopic analysis is presented. Samples are digested by fusion in the presence of a lithium borate flux at 1100 °C and dissolved whilst molten in dilute nitric or hydrochloric acid. Prior to chemical separation using ion exchange techniques, Li and B from the flux material and Si from the sample are separated from the remaining major elements, REE and high field strength elements (HFSE) in the sample by Fe-hydroxide co-precipitation. The chemical separation of Hf is a two-stage procedure designed to first remove the remaining matrix elements (e.g. Fe, Ba) in the sample using standard cation exchange techniques, followed by separation of Hf from the REE and HFSE on TEVA extraction chromatographic resin. Hf yields are >90% and total procedural blanks are ca. 50 pg. Hf isotope ratios of a synthetic standard solution and replicate digestions of international rock standards BHVO-1 and BCR-1 measured on multi-collector inductively coupled plasma mass spectrometer (MC-ICPMS) reproduce similarly to ≤50 ppm (2 S.D.). The following elemental ratios are routinely obtained for elements, which interfere isobarically or may affect the ionisation and/or fractionation behaviour of Hf during analysis: 176Yb/176Hf<0.0001; 176Lu/176Hf<0.00001; Ti/Hf<0.05. This technique also provides a means of separating Nd from the REE fraction for isotopic analysis and, potentially, may be adapted for measurement of Lu/Hf ratios by isotope dilution techniques. 相似文献
11.
Katherine E. Zink Denise A. Tarnowski Mark J. Mandel Laura M. Sanchez 《Journal of mass spectrometry : JMS》2020,55(4)
Tissue sections have long been the subject matter for the application of imaging mass spectrometry, but recently the technique has been adapted for many other purposes including bacterial colonies and 3D cell culture. Here, we present a simple preparation method for unsectioned invertebrate tissue without the need for fixing, embedding, or slicing. The protocol was used to successfully prepare a Hawaiian bobtail squid hatchling for analysis, and the resulting data detected ions that correspond to compounds present in the host only during its symbiotic colonization by Vibrio fischeri. 相似文献
12.
F. Groppi E. Persico E. Quartapelle M. Gallorini L. Bergamaschi M. C. Cantone 《Journal of Radioanalytical and Nuclear Chemistry》2008,278(3):595-598
Radioactive solutions of 177g,mLuIIICl3 are used for labeling organic compounds for metabolic radiotherapy and radioimmunotherapy. The labeling process involves
Lu in III oxidation state, so the presence of other stable impurities in the same oxidation state could result in an isomorphous
dilution of radioactive 177gLu. Samples of 177gLuCl3 were analyzed to quantify the chemical impurities with a special regard for trivalent elements with instrumental neutron
activation analysis (INAA), carried out in the research nuclear reactor TRIGA MARK II (GA, USA) of the Università degli Studi
di Pavia, and electrothermal atomic absorption spectroscopy (ET-AAS) (Varian, USA) at LASA. 相似文献
13.
Polypyrrole is one of the most frequently studied conducting polymers, having high electrical conductivity and stability,
suitable for multi-functionalised applications. Coatings of chemically synthesised polypyrrole applied onto various organic
and inorganic materials, such as polymer particles and films, nanoparticles of metal oxides, clay minerals, and carbon nanotubes
are reviewed in this paper. Its primary subject is the formation of new materials and their application in which chemical
oxidative polymerisation of pyrrole was used. These combined materials are used in antistatic applications, such as anti-corrosion
coating, radiation-shielding, but also as new categories of sensors, batteries, and components for organic electronics are
created by coating substrates with conducting polymer layers or imprinting technologies. 相似文献
14.
Solution-phase synthesis of inorganic nanostructures by chemical transformation from reactive templates
下载免费PDF全文
![点击此处可从《中国科学:化学》网站下载免费的PDF全文](/ch/ext_images/free.gif)
HUANG Teng & QI LiMin Beijing National Laboratory for Molecular Sciences State Key Laboratory for Structural Chemistry of Unstable Stable Species College of Chemistry Peking University Beijing China 《中国科学:化学》2010,(2)
The solution-phase synthesis by chemical transformation from reactive templates has proved to be very effective in morphology-controlled synthesis of inorganic nanostructures. This review paper summarizes the recent progress in solution-phase synthesis of one-dimensional and hollow inorganic nanostructures via reactive templates, focusing on the approaches developed in our lab. The formation mechanisms based on reactive templates are discussed in depth to show the general concepts for the preparation proces... 相似文献
15.
《Electrochemistry communications》2003,5(10):862-866
An infrared spectroscopic investigation of inorganic fillers employed in composite perfluorosulfonic membranes has been carried out. The surface acidity of the fillers appears to influence the bending and stretching vibrational frequencies of the water physically adsorbed on the filler surface. The conductivity of composite membranes and maximum power density of direct methanol fuel cells (DMFCs) at 145 °C appear to be related to the characteristics of the water adsorbed on the filler particles. Inorganic fillers characterised by acidic properties undergo a strong interaction with water and enhance the DMFC performance at high temperature. 相似文献
16.
An INAA technique employing beta spectrometry was developed for the determination of phosphorus in polymers. The (n,γ) reaction
on phosphorus produces32P, half-life 14.3 days, a pure beta emitter with end-point energy 1.71 MeV. Polymer samples in the form of powders, films
and pellets are irradiated and then counted with a plastic scintillator. The beta spectrum is corrected for interferences
(especially Sb, Zn and Br which are quantified by gamma spectrometry) and for energy loss in the thick sample. Samples must
also be analyzed for S and Cl which cause nuclear interferences. With an irradiation time of 4 hours at a neutron flux of
5·1011 n·cm−2
s
−1, decay time 10 days and counting time 10 minutes, the sensitivity is 520 counts/μg phosphorus and the detection limit is
typically 2μg/g. 相似文献
17.
Alok Srivastava D. Pathania K. K. Swain Nicy Ajith R. Acharya A. V. R. Reddy H. Nayyar 《Journal of Radioanalytical and Nuclear Chemistry》2012,294(2):315-318
The phyto-accumulation efficacy of selenium (Se) from soil by chickpea plant is reported. Chickpea plants were grown in soil having different concentrations (1–4 mg kg?1) of Se. Samples of soil and different parts of chickpea plants in Se rich soil were analyzed for determination of Se concentrations by instrumental neutron activation analysis (INAA). Samples were irradiated in self-serve facility of CIRUS reactor, BARC, Mumbai at a neutron flux of the order of 1013 cm?2 s?1. The gamma activity at 264.7 keV of 75Se (119.8 d) was measured using a 45% relative efficiency HPGe detector coupled to MCA. Dependence of Se distribution in soil and plants on its spiking concentration was evaluated in this work. The Se concentrations determined in plant parts grown in control soil and in soil spiked with Se (4 mg kg?1) are in the range of 0.6–0.8 and 65–68 mg kg?1 respectively. 相似文献
18.
Bioprospecting for new marine natural products (NPs) has increased significantly over the last decades, leading to an unprecedented discovery of new molecules. Marine invertebrates have been the most important source of these NPs, with researchers commonly targeting particular taxonomic groups, marine regions and/or molecules from specific chemical groups. The present review focuses on new NPs identified from marine invertebrates between 2000 and 2009, and performs a detailed analysis on: (1) the chemical groups of these NPs; (2) the association of particular chemical groups to specific marine invertebrate taxa; and (3) the yielding of molecules from the same chemical group from organisms occurring in a particular geographic region. Our survey revealed an increasing number of new terpenoids being discovered between 2000 and 2009, contrasting with the decreasing trend in the discovery of new alkaloids and aliphatic molecules. Overall, no particular association was identified between marine invertebrate taxa and chemical groups of new NPs. Nonetheless, it is worth noting that most NPs recorded from cnidarians and mollusks were terpenoids, while most NPs identified in echinoderms were aliphatic compounds or carbohydrates. The geographical trends observed in our study do not support the idea of particular chemical groups of new NPs being associated with marine invertebrates from any specific geographical region, as NPs from different chemical groups were commonly distributed worldwide. 相似文献
19.
Assessing soil pollution from a municipal waste dump in Islamabad, Pakistan: a study by INAA and AAS
S. Waheed N. Siddique Q. Hamid M. M. Chaudhry 《Journal of Radioanalytical and Nuclear Chemistry》2010,285(3):723-732
INAA and AAS techniques have been employed to determine 40 elements in soil of a municipal waste dump in sector H-11, Islamabad. Background soil was also analyzed to study the extent of contamination of the dump site soil. Most of the major elements in these soils represented the geochemical composition of the soil in this area. The enrichment factors for quantified elements identified high Sb and Mg contents that could be attributed to the presence of PET and food materials in the waste. Geo-accumulation Index (I geo), Pollution Index (PI) and the Integrated Pollution Index (IPI) have also been calculated for all elements. The values for these indices show that municipal waste has distorted the soil ambiance and the soil of waste dump site is slightly to moderately polluted as compared to the background soil. The dump soil was found to be moderately polluted by the elements Ba, Br, Ga, Rb, Zn, Ni and Pb. Significantly high Cu, Mg and Sb contamination was observed for the waste soil that is likely to pose an environmental issue if current waste disposal procedures are continuously employed. 相似文献
20.
In the framework of the research program Synchronization of Civilizations in the Eastern Mediterranean Region in the 2nd Millenium B.C. instrumental neutron activation analysis (INAA) was used to determine 30 elements in pumice from archaeological excavations to reveal their specific volcanic origin. The widespread pumiceous products of several eruptions in the Aegean region were used as abrasive tools and were therefore popular trade objects. A remarkable quantity of pumice and pumiceous tephra (several km3 ) was produced by the Minoan eruption ofThera (Santorini), which is assumed to have happened between 1450 and 1650 B.C. Thus the discovery of the primary fallout of Minoan tephra in archaeologically stratified locations can be used as a relative time mark. Additionally, pumice lumps used as abrasive can serve for dating by first appearance. Essential to an identification of the primary volcanic source is the knowledge that pumices from the Aegean region can easily be distinguished by their trace element distribution patterns, as previous work has shown. The elements Al, Ba, Ca, Ce, Co, Cr, Cs, Dy, Eu, Fe, Hf, K, La, Lu, Mn, Na, Nd, Rb, Sb, Sc, Sm, Ta, Tb, Th, Ti, U, V, Yb, Zn and Zr were determined in 16 samples of pumice lumps from excavations in Tell-el-Dab'a and Tell-el-Herr (Egypt). Two irradiation cycles and five measurement runs were applied. A reliable identification of the samples is achieved by comparing these results to the database compiled in previous studies. 相似文献