Meeting the need for reference measurements

Summary Reference materials do fulfil a very useful function in that they provide means to check, verify and calibrate measurement procedures and instrumentation. However, the material is often idealized compared to real life samples: it is either (very) pure or does not correspond in concentration level or matrix to the real life case. It is shown how this situation could be remedied if real life samples with carefully assessed reference values could be made available regularly as unknowns to measurement laboratories. Comparison of the latter's measurements with the reference values then would provide a picture of the real performance of the particular measurement community in general and of each participating laboratory in particular. The opinion is expressed that isotope-specific methods have now matured to the stage that, if they are correctly applied under rigorous control and based on highly skilled expertise, they can provide such reference values against which laboratories can then evaluate their routine performance in regular Interlaboratory Measurement Evaluation Programmes (IMEPs).

---

Wie der Notwendigkeit von Referenzmessungen entsprochen werden kann

     

Certification of reference materials by European Commission services

The programmes of the European Commission for the certification of reference materials are presented: the Standards, Measurement and Testing Programme (formerly BCR Programme) funds research and development aiming at improved ability to measure and at improved comparability of measurements; reference materials result from many of its projects; the Institute for Reference Materials and Measurements (formerly CBNM) prepares some of these, stores nearly all of them, will distribute them from 1995 on and certifies some additional ones. The principles adopted for the certification of BCR reference materials are explained. The procedure for a typical matrix reference material is that a group of laboratories first refines their methods (e.g. by intercomparisons and technical discussion) until they achieve agreement of results to within random experimental error and then analyses the reference material; certified value and uncertainty are calculated on the basis of their results. Recent achievements and projects in progress are listed.     

Understanding the properties of isospectral points and pairs in graphs: The concept of orthogonal relation

The mathematical property orthogonal relationship is used in proving the fact that isospectrality, isocodality and isocoefficiency of vertices within a graph are all equivalent. The same is true for isospectrality, strict isocodality and strict isocoefficiency of pairs (including edges) within a graph, whereas the weak versions of the latter properties are necessary but not sufficient for isospectrality of pairs. Similarly, necessary and sufficient conditions for isospectrality of vertices and pairs in different graphs are derived. In all these proofs, the concept of orthogonal relation plays a major role in that it allows the use of tools of elementary linear algebra.     

Cabbage leaves CL-1 certified reference material for the trace analysis of plant materials

Summary The preparation of cabbage leaves (CL-1) certified reference material and homogenisation procedures are described and relevant data are compiled. In evaluation of the data four concurrent tests (Dixon's, Grubb's, Nalimov's and the test of coefficient of Kurtosis) for outlier rejection at the significance level 0.05 have been applied. As a result it was possible to establish certified concentration values for 10 elements and reference values for 4 elements.

---

Zertifiziertes Referenzmaterial Cabbage Leaves CL-1 für die Spurenanalyse von pflanzlichem Material

     

Structure-reactivity problem in cycloaddition reactions to form heterocyclic compounds

The steric and electronic effects of substituents in both diene and dienophile components have been considered as the main factors that control the electronic character of (4+2)-cycloaddition leading to transitions between normal, neutral, and inverse Diels-Alder reactions.Institut für Organische Chemie der Universität Regensburg, Universitätsstr. 31, D-93040 Regensburg, Germany. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1307–1322, October, 1995. Original article submitted August 15, 1995.     

Zur Literaturdokumentation in der Analytischen Chemie

Zusammenfassung Der in den Referatezeitschriften Chemical Abstracts, Analytical Abstracts und Fresenius Zeitschrift für Analytische Chemie erkennbare alphabetischsystematische Aufbau der Indexregister wird dargestellt und beurteilt. Die Beispiele stammen aus den Indexabschnitten Atomabsorptionsspektrometrie (Methode), Phenole (Stoff) und Boden (Material). Unter Berücksichtigung der Ergebnisse werden Vorschläge zur benutzerfreundlichen Gestaltung eines analytisch-chemischen Indexsystems nach einer 3-W-Regel (Fragen nach WAS, WIE und WORIN, WOZU?) gemacht und diese Anforderungen an einer Stichprobe von 47 Referaten von Veröffentlichungen aus 21 verschiedenen Zeitschriften in den Indices der Referatzeitschriften überprüft. Die Recall-Raten nach den vorgegebenen Schlüsselwörtern für jede Teilfrage der 3-W-Regel liegen zwischen 3 und 51% und für die Frage nach der Methode mit 3–14% am niedrigsten.

---

Literature documentation in analytical chemistryIII. Structure and valuation of index systems

Summary The recognizable alphabetic-sytematic structure of the indices in the abstract journals Chemical Abstracts, Analytical Abstracts and Fresenius Zeitschrift für Analytische Chemie is described and criticized. The examples are taken from the index sections atomic absorption spectrometry (method), phenols (substance) and soil (material). In consideration of the results and taking into account the needs of the user suggestions for the construction of an analytical-chemical index system according to a 3-Wprinciple (questions for what, in what way and wherein, whereto) are given, and these requirements are proved by a random sample of 47 abstracts from publications of 21 diverse journals taken from the indices of the abstract journals. The recall ratios resulting from the pretended key words for every sectional question of the 3-W-priciple are between 3 and 51%; for the question as to the method they are most inferior with 3–14%.

---

---

Teil II siehe Fresenius Z Anal Chem 304:28 (1980)     

Plutonium in soils, bottom sediments and lichen near peaceful nuclear explosion sites in the Republic of Sakha (Yakutia)

During the 1974–1987 period 12 paceful nuclear explosions were conducted in the Republic of Sakha (Yakutia). For the first time^239,240Pu and²³⁸Pu concentrations were determined in samples of soils, bottom sediments and lichen taken at the Craton-3 and Crystal nuclear explosion sites. At the Craton-3^239,240Pu concentrations in the range 6.2 mBq/g to 5.9 Bq/g samples of soil and^239,240Pu concentrations up to 7.4 Bq/g in samples of lichen were observed.^239,240Pu concentration measurements in bottom sediments of a stream washing out the banking around the borehole of Craton-3 show that plutonium migrates in the direction of the Markha river. At the Crystal site local plutonium concentrations up to 35 Bq/g in soil and 1.8 Bq/g in lichen were observed.     

The diagram lattice as structural principle A. New aspects for representations and group algebra of the symmetric group B. Definition of classification character,mixing character,statistical order,statistical disorder; A general principle for the time evolution of irreversible processes

It is the aim of this paper to demonstrate the significance of the diagram lattice. This lattice was defined in order to achieve structural insight into the phenomenon of chirality in chemistry. In this context, Theorie der Chiralitätsfunktionen [1] may serve as reference. In the introduction of the present paper a summary of the relevant theorems and definitions is given and a few examples of the diagram lattice are graphically illustrated. Parts A and B can be read independently and presuppose knowledge only of the introduction. Part A is of special interest for mathematicians, Part B and [1] for physicists and chemists.In Part A theorems on the representations of the group _n and certain subgroups of it and on the structure of the group algebra are developed. In Part B the concept classification character with the two complementary aspects of identification and distinction is derived. With the interpretation mixing character the partial order relation gains an interpretation through a mixing process, which can be expressed by a bistochastic matrix. This results in another equivalent definition of the diagram lattice. Interpreted as mixing character of a statistical distribution a diagram represents statistical order and statistical disorder by its row partition and column partition respectively. These concepts and the corresponding lattice structure lead to the hypothesis of growing mixing character as a criterion for the time evolution of isolated systems. The criterion of increasing entropy provides a much weaker condition. A discussion of the master equation leads to a proof of the principle of growing mixing character.[/p]     

Determination of molecular properties by the method of moments

Some precautions needed in the choice of weight functions when calculating wave functions by the method of moments are analysed. It appears that an important criterion for good weight functions is that the difference between the total and the truncated overlaps (both defined in the paper) be high.The method of moments is applied to wave functions involving Hylleraas-type correlation factors using weight functions made up of products of single-particle orbitals. The aim of the calculations is partly to test the criteria for good weight functions, partly a preparation of more extended calculations of a similar type.The new name of the institute is: Computer Application Research and Development Center of the Chemical Industries.     

Multivariate Statistical Assessment of Air Quality: A Case Study

The present paper deals with the application of several chemometrical methods (cluster and principal components analysis, source apportioning on absolute principal components scores) to an aerosol data collection from Unterloibach, Austria. It is shown that seven latent factors explaining almost 80% of the total variance are responsible for the data structure and are conditionally identified as secondary aerosol, mineral dust, oil burning, lead smelter, coal burning, salt and fertilizer emission sources. Furthermore, the contribution of each identified source to the formation of the particle total mass and chemical compounds total concentration is calculated. Thus, a reliable assessment of the air quality in the region is performed. The requirements of the sustainability concept for ecological indicators in this case is easily transformed into a multivariate statistical problem taking into account not separate indicators but the specific multivariate nature of aerosol pollution.