Guidelines for terms related to chemical speciation and fractionation of elements. Definitions, structural aspects, and methodological approaches (IUPAC Recommendations 2000)

2000 ◽  
Vol 72 (8) ◽  
pp. 1453-1470 ◽  
Author(s):  
Douglas M. Templeton ◽  
Freek Ariese ◽  
Rita Cornelis ◽  
Lars-Göran Danielsson ◽  
Herbert Muntau ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Isotopic Composition ◽  
Chemical Speciation ◽  
Chemical Species ◽  
Electronic States ◽  
Speciation Analysis ◽  
General Outline ◽  
Methodological Approaches ◽  
Structural Aspects

This paper presents definitions of concepts related to speciation of elements, more particularly speciation analysis and chemical species. Fractionation is distinguished from speciation analysis, and a general outline of fractionation procedures is given. We propose a categorization of species according to isotopic composition of the element, its oxidation and electronic states, and its complex and molecular structure. Examples are given of methodological approaches used for speciation analysis. A synopsis of the methodology of dynamic speciation analysis is also presented.

Guidelines for Terms Related to Chemical Speciation and Fractionation of Elements. Definitions, Structural Aspects, and Methodological Approaches

2016 ◽  
Author(s):  
Douglas M. Templeton ◽  
Freek Ariese ◽  
Rita Cornelis ◽  
Lars-Göran Danielsson ◽  
Herbert Muntau ◽  
...  
Keyword(s):  
Chemical Speciation ◽  
Methodological Approaches ◽  
Structural Aspects

Molecular Structure of the Outermost Cell Wall Component of Spirillum Serpens

1977 ◽  
Vol 35 ◽  
pp. 342-343
Author(s):  
Wah Chiu ◽  
David Grano
Keyword(s):  
Molecular Structure ◽  
Cell Wall ◽  
Outer Membrane ◽  
Gel Electrophoresis ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Cell Wall Component ◽  
Protein Components ◽  
Exposure Technique ◽  
Structural Aspects

The periodic structure external to the outer membrane of Spirillum serpens VHA has been isolated by similar procedures to those used by Buckmire and Murray (1). From SDS gel electrophoresis, we have found that the isolated fragments contain several protein components, and that the crystalline structure is composed of a glycoprotein component with a molecular weight of ∽ 140,000 daltons (2). Under an electron microscopic examination, we have visualized the hexagonally-packed glycoprotein subunits, as well as the bilayer profile of the outer membrane. In this paper, we will discuss some structural aspects of the crystalline glycoproteins, based on computer-reconstructed images of the external cell wall fragments.The specimens were prepared for electron microscopy in two ways: negatively stained with 1% PTA, and maintained in a frozen-hydrated state (3). The micrographs were taken with a JEM-100B electron microscope with a field emission gun. The minimum exposure technique was essential for imaging the frozen- hydrated specimens.

Recent Advances in Speciation Analyses of Tobacco and Other Important Economic Crops

2020 ◽  
Vol 17 ◽  
Author(s):  
Zhiping Jiang ◽  
Zhizhang Tian ◽  
Chuntao Zhang ◽  
Dengke Li ◽  
Ruoxin Wu ◽  
...  
Keyword(s):  
Method Comparison ◽  
Chemical Species ◽  
Complete Information ◽  
Speciation Analysis ◽  
Elemental Content ◽  
Specific Element ◽  
Balance Accuracy ◽  
Comprehensive Knowledge ◽  
Total Elemental Content ◽  
The Impact

Background: Speciation analysis is defined as the analytical activities of identifying and/or measuring the quantities of one or more individual chemical species in a sample. The knowledge of elemental species provides more complete information about mobility, bioavailability and the impact of elements on ecological systems or biological organisms. It is no longer sufficient to quantitate the total elemental content of samples to define toxicity or essentiality. Thus speciation analysis is of vital importance and generally offers a better understanding of a specific element. Discussion: Thorough speciation scheme consisting of sampling, sample preparation, species analysis and evaluation were described. Special emphasis is placed on recent speciation analysis approaches including both direct and coupling methods. A current summary of advantages and limitations of the various methods as well as an illustrative method comparison are presented. Certain elements and species of interest are briefly mentioned and practical examples of speciation applications in tobacco and other important economic crops are also discussed. Aim/Conclusion: This review aims to offer comprehensive knowledge about elemental speciation and provide readers with valuable information. Many strategies have been developed for the determination of multiple elemental species in tobacco and other important economic crops. Nevertheless, it is an eternal pursuit to establish speciation methods which can balance accuracy, agility as well as universality.

Chemical speciation of heterogeneously reduced Pu in synthetic brines

2006 ◽  
Vol 94 (5) ◽  
Author(s):  
Mei Ding ◽  
James L. Conca ◽  
Christophe Den Auwer ◽  
Rinat I. Gabitov ◽  
Nancy J. Hess ◽  
...  
Keyword(s):  
Fine Structure ◽  
New Mexico ◽  
Pilot Plant ◽  
Chemical Speciation ◽  
Speciation Analysis ◽  
Waste Isolation Pilot Plant ◽  
X Ray ◽  
Xafs Spectroscopy ◽  
Heterogeneous Reduction ◽  
X Ray Absorption

SummaryX-ray absorption fine structure (XAFS) spectroscopy has been used to determine the speciation of Pu precipitates prepared by the heterogeneous reduction of Pu(VI) with Al and Fe in 5 M NaCl and an ERDA-6 brine, a simulant from the Waste Isolation Pilot Plant in Carlsbad, New Mexico. NaOCl was added to some of these solutions to determine its effect on Pu speciation. Analysis of the Pu

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