Topical Problems in Elemental Analysis of Advanced Ceramic Materials

Selected prominent problems in the analysis of advanced ceramic materials are surveyed. The importance of reliability of results is discussed in the field of elemental trace- and microanalysis in view of its interaction with economy, power of detection, local resolution and speciation selectivity. Particular problems in the analysis of major constituents, trace components and microlocal distributions are based on the striking propertics of ceramics; they are exemplified. Analytical assistance must start from the beginning of the production processing, in the preparation of the powdered base materials. Determination of the stoichiometry requires high accuracy and differentiation of chemical species in bulk and surface analysis of ceramic base powders. Element trace determination by direct instrumental methods requires standard reference materials for calibration; these are currently inavailable in a sufficient variety. For optimum reliability and power of detection, element traces must be prepared in isolated form in a small excitation volume for analysis. A review on the state-of-the-art of wet-chemical combined procedures is presented. Decomposition position procedures are emphasized, due to their risk of contributing severe systematic error. Combustion in elementary fluorine is presented for decomposition of refractory materials. The performance of some direct procedures is discussed. Very efficient methods are available for element trace determinations in ceramic materials, offering high detection power. Several approaches for high-resolution local microanalysis in non-conductive ceramic materials are identified as the most promising development in the analysis of sintered compact ceramic products and devices.     

Fractionation analysis of iodine in bovine milk by preconcentration neutron activation analysis

Iodine is an essential trace element for human beings. The main source of iodine is generally food items such as fish and milk. Either the lack or the excess of iodine can cause health problems. There exists an increasing interest in the determination of total iodine as well as various species of iodine in milk. We have developed an epithermal neutron activation analysis method with a Compton suppression (ENAA-CS) counting system for the determination of ng mL⁻¹ levels of iodine. We have also employed chemical separation methods prior to ENAA-CS to measure the fraction-specific concentrations of iodine in bovine milk. We have measured the following iodine concentrations in homogenized milk (3.25%milk fat): 0.48 ± 0.02 μg mL⁻¹ of total iodine, 0.020 ± 0.003 μg mL⁻¹ of lipid-bound iodine, 0.039 ± 0.002, 0.019 ± 0.002 and 0.021 ± 0.004 μg mL⁻¹ of protein-bound iodine depending on the protein separation method and 0.45 ± 0.02 μg mL⁻¹ of inorganic species.     

Critical comparison of radiometric and mass spectrometric methods for the determination of radionuclides in environmental, biological and nuclear waste samples

The radiometric methods, alpha (α)-, beta (β)-, gamma (γ)-spectrometry, and mass spectrometric methods, inductively coupled plasma mass spectrometry, accelerator mass spectrometry, thermal ionization mass spectrometry, resonance ionization mass spectrometry, secondary ion mass spectrometry, and glow discharge mass spectrometry are reviewed for the determination of radionuclides. These methods are critically compared for the determination of long-lived radionuclides important for radiation protection, decommissioning of nuclear facilities, repository of nuclear waste, tracer application in the environmental and biological researches, these radionuclides include ³H, ¹⁴C, ³⁶Cl, ⁴¹Ca, ^59,63Ni, ^89,90Sr, ⁹⁹Tc, ¹²⁹I, ^135,137Cs, ²¹⁰Pb, ^226,228Ra, ²³⁷Np, ²⁴¹Am, and isotopes of thorium, uranium and plutonium. The application of on-line methods (flow injection/sequential injection) for separation of radionuclides and automated determination of radionuclides is also discussed.     

电感耦合等离子体质谱、中子活化分析及其它谱学方法测定环境、生物样品中铝形态和含量研究进展

本文综述了上世纪90年代以来电感耦合高频等离子体质谱(ICP-MS)、中子活化分析(NAA)以及其它谱学方法测定环境生物样品中铝形态的研究进展,共引用文献60篇。     

四川某金矿中非金属单矿物的元素分析及意义

利用中子活化分析法对四川某地区的非金属单矿物(热液脉矿物)的元素进行了测试,并利用元素地球化学研究方法对元素间的相关关系进行了分析。结果表明,在该地区可以利用元素间的伴生关系指导找矿。     

Classical analysis including trace-matrix separation versus solid state mass spectrometry: A comparative study for the analysis of high purity Mo,W and Cr

The applicability of GDMS, SIMS, SSMS, NAA and TMS with AAS, ICP-OES and ICP-MS end determination for routine bulk ultratrace analysis of high purity refractory metals was investigated. Due to the heterogeneous distribution of trace elements in the sub-ppm range, sample consumption and analysis time have a tremendous influence on quantification with procedures of low sample consumption. As an example, GDMS, which is commonly used for ultrapure material certification by most of the manufacturers in Europe and the USA, exhibits discrepancies by more than one order of magnitude for repetitive analyses of a series of trace components in the same sample. Furthermore, results of different laboratories using the same instrument are frequently not comparable. Due to easy standardization and large sample consumption TMS procedures combined with FAAS, GFAAS, ICP-AES and ICP-MS as methods of end determination exhibit better precision and accuracy than GDMS and SIMS. Detection limits are comparably low or even better in case of ICP-MS end determination. TMS procedures are less expensive and less time consuming than highly sophisticated analytical techniques like GDMS, SIMS or NAA. Additionally, they can be easily applied by experienced personnel in a well equipped industrial analytical laboratory.List of Acronyms Used AAS Atomic Absorption Spectrometry - FAAS Flame Atomic Absorption Spectrometry - GDMB Gesellschaft Deutscher Metallhütten- und Bergleute - GDMS Glow Discharge Mass Spectrometry - GFAAS Graphite Furnace Atomic Absorption Spectrometry - ICP-AES Inductively Coupled Plasma Atomic Emission Spectrometry - ICP-MS Inductively Coupled Plasma Mass Spectrometry - IDMS Isotope Dilution Mass Spectrometry - NAA Neutron Activation Analysis - SIMS Secondary Ion Mass Spectrometry - SSMS Spark Source Mass Spectrometry - TMS Trace-Matrix Separation - VLSI Very Large Scale Integration - XRFS X-Ray fluorescence Spectroscopy Dedicated to Professor Günther Tölg on the occasion of his 60th birthday     

A review on speciation of iodine-129 in the environmental and biological samples

As a long-lived beta-emitting radioisotope of iodine, ¹²⁹I is produced both naturally and as a result of human nuclear activities. At present time, the main part of ¹²⁹I in the environment originates from the human nuclear activity, especially the releases from the spent nuclear fuel reprocessing plants, the ¹²⁹I/¹²⁷I ratios have being reached to values of 10⁻¹⁰ to 10⁻⁴ in the environment from 10⁻¹² in the pre-nuclear era. In this article, we review the occurrence, sources, inventory, and concentration level of ¹²⁹I in environment and the method for speciation analysis of ¹²⁹I in the environment. Measurement techniques for the determination of ¹²⁹I are presented and compared. An overview of applications of ¹²⁹I speciation in various scientific disciplines such as radiation protection, waste depository, and environmental sciences is given. In addition, the bioavailability and radiation toxicity (dose to thyroid) of ¹²⁹I are discussed.     

REE bound polysaccharides in leaves of Dicranopteris dichotoma by MAA

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NAA and Mössbauer Study on the Colorative Mechanism of Yaozhou Celadon in Ancient China

The contents of 30 colorative elements in the glaze of Yaozhou celadon have been measured by neutron activation analysis (NAA) with the conclusion that iron is the dominant colorative element. It is further detected by Mössbauer spectroscopy that the iron in the glaze exists in the chemical state of structural iron (Fe²⁺, Fe³⁺) and that there is quantitative relation between the dominant wavelength of various colored glazes and the relative content of structural iron. Thus the colorative mechanism of Yaozhou celadon has been revealed entirely.     

Solid phase extraction for the speciation and preconcentration of inorganic selenium in water samples: A review

Selenium is an essential element for the normal cellular function of living organisms. However, selenium is toxic at concentrations of only three to five times higher than the essential concentration. The inorganic forms (mainly selenite and selenate) present in environmental water generally exhibit higher toxicity (up to 40 times) than organic forms. Therefore, the determination of low levels of different inorganic selenium species in water is an analytical challenge. Solid-phase extraction has been used as a separation and/or preconcentration technique prior to the determination of selenium species due to the need for accurate measurements for Se species in water at extremely low levels. The present paper provides a critical review of the published methods for inorganic selenium speciation in water samples using solid phase extraction as a preconcentration procedure. On the basis of more than 75 references, the different speciation strategies used for this task have been highlighted and classified. The solid-phase extraction sorbents and the performance and analytical characteristics of the developed methods for Se speciation are also discussed.