Determination des fonctions d'excitation des reactions19F(p, α0)16O et7Li(p, α0)4He entre 150 et 1800 keV

The experimental device used is described. Excitation functions are given for an angle of observation 150° with respect to the incident beam. The possibilities of applying these reactions to the measurement of surface lithium and fluorine concentrations are considered. The detection limits for these two elements are shown to be 5·10⁻³ μg·cm⁻² with protons of energy between 1,350 and 1,500 keV. The method is compared with that based on the detection of prompt γ-rays from the reactions⁷Li(p, γ)⁸Be and¹⁹F(p, α γ)¹⁶O.      

Direct determination of cadmium in high-purity metals by flame atomic fluorescence spectrometry

Raschig rings used as a safety mechanism, to avoid critical reactions in solutions containing radioactive materials, are usually made of borosilicate glass. Since boron is the active neutron absorbing ingredient, it is important to determine the boron content in the Raschig rings at any given time. A method has been developed to determine rapidly the boron content of borosilicate glasses. Ion exchange and potentiometric measurement are used to determine boron as the tetrafluoroborate ion. The precision of the method is ±2.0 mV. The average difference between values of a wet chemical analysis and those of the potentiometric method is 7.7%.     

Über Spurenelementbestimmungen in Leberproben Mittels Protoneninduzierter Röntgenfluoreszenz (Pixe)

Multi-element-analysis by PIXE in respect to medical applications is discussed. Examples of trace-element determinations in liver tissues are given, demonstrating the applicability and usefulness of this rather new analytical technique.      

Highly Selective Ion-Sensitive Electrodes Based on Dibenzo-Crown Ethers Containing Functional Groups for the Determination of Potassium in Biological Fluids

The electrochemical properties of membranes based on dibenzo-crown ethers bearing hydroxyl and chloromethyl groups in polyether rings were studied. These substances were tested as membrane ionophores for ion-selective electrodes (ISEs) reversible to potassium ion. The developed ISEs were used for determining potassium in blood plasma samples. The generalized results of determining potassium in the blood of different patients with cardiovascular diseases revealed quantitative regularities that allowed the diseases to be diagnosed early.     

Die kathodische Sauerstoffreduktion an pyrolytisch abgeschiedenem Kohlenstoff in peroxidhältigen alkalischen Elektrolyten

The kinetics of the system O₂/HO₂ ^?, OH^? were studied at pyrolytic carbon in alkaline electrolytes. The rest potentials are close to the reversible values. They decrease by 30 mV when the HO₂ ^?-concentration is increased by a factor 10. CathodicTafel lines displayb-values between 70 and 95 mV. The exchange current densities are evaluated by extrapolation ofTafel lines to zero overvoltage and from the charge transfer resistance. Two different succeeding charge transfer reactions occur in course of the overall process, the first of which is the rate-determining step. A cathodic reaction order of zero is obtained with respect to HO₂ ^?. Theb values of anodicTafel lines are between 60 and 80 mV, the corresponding reaction order concerning the HO₂ ^? concentration is found to be +0.5. The kinetic studies prove the reversibility of the system O₂/HO₂ ^?, OH^? at carbon electrodes. The reaction mechanism is: $$\begin{array}{*{20}c} {O_2 + e^ - \rightleftarrows O_2 } \\ {O_{2^ - } + H_2 O \rightleftarrows HO_2 + OH - } \\ {HO_2 + e^ - \rightleftarrows HO_{2^ - } } \\ \end{array} $$ .     

Collision-induced rotational transitions in nali(1Π)

Collision-induced rotational transitions in the electronically excited NaLi molecule have been studied using laser excited fluorescence. Due to the greater number of allowed transitions as compared with Na₂ and Li₂, more cases were found of transitions +ΔJ and ?ΔJ having greatly different cross sections (“+/ - asymmetry”). This observation is in agreement with recent predictions on the basis of Born's approximation. All observed transitions are classified according to the symmetry of the contributing potential terms. Data are presented which indicate the necessity for refinements of the theory.     

Analytical application of embelin

Summary Embelin is employed as a reagent for the gravimetric individual estimation of alkaline earth metals and magnesium.

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Zusammenfassung Zur gravimetrischen Einzelbestimmung von Magnesium und den Erdalkalien wird Embelin als Reagens empfohlen.

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Part III: Z. analyt. Chem. 185, 216 (1962).     

Phenylimino-phosphorsäure-(diäthylamid)-chloride

Zusammenfassung Monomere Phosphinimine der allgemeinen Formel C₆H₅N= =PCl _n (NEt₂)_3-n (n=0,1,2) lassen sich (I) aus dimerem Phenylimino-phosphorsäure-trichlorid und Diäthylamin in Gegenwart eines Chlorwasserstoffakzeptors und (II) durch Reaktion der Phosphine PCl _n (NEt₂)_3-n mit Phenylazid darstellen. Die Phosphorane Et₂NPCl₄, (Et₂N)₂PCl₃ und (Et₂N)₃PBr₂ reagieren mit Anilin nicht zu Phenylimino-Verbindungen. Durch alkalische Hydrolyse von C₆H₅N=PCl(NEt₂)₂ entsteht das Phosphorsäure-bis[diäthylamino]-anilid. Die IR- und¹H- und³¹P-NMR-Spektren der Verbindungen werden mitgeteilt.

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Monomeric phosphinimines of the general formula C₆H₅N= =PCl _n (NEt₂)_3-n (n=0,1,2) are formed (I) from dimeric phenyliminophosphoricacid-trichloride and diethylamine in the presence of a HCl-acceptor and (II) by reacting the phosphines PCl _n (NEt₂)_3-n with phenylazide. The phosphoranes Et₂NPCl₄, (Et₂N)₂PCl₃ and (Et₂N)₃PBr₂ do not give the corresponding phenylimines with aniline. Alkaline hydrolysis of C₆H₅N= =PCl(NEt₂)₂ gives bis[diethylamino]-anilido-phosphinoxid. IR-,¹H- and³¹P-NMR-spectra are given.

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Mit 1 Abbildung     

Use of γ-γ Coincidence Spectrometry in the Geochemical Study of Diamictites from South Africa

We used - coincidence spectrometry to investigate the possible presence of a meteoritical component in 27 samples of South African diamictites. Recently, several studies have suggested that some tillites/diamictites may represent impact breccias, but a petrographical study by our group found no evidence for the presence of impact-characteristic shocked minerals. The siderophile elements, such as Cr, Co, Ni, and, especially, the platinum group elements, have high abundances in meteorites, but low abundances in terrestrial crustal rocks. The Ir content of the diamictites was measured with the new iridium coincidence spectrometer (ICS) at the University of Vienna, with detection limits of around 0.02 ppb. No enrichments in the contents of Ir and other siderophile elements compared to average crustal concentrations were found; thus, no unequivocal evidence for an impact origin of these diamictites of the South African Dwyka Group can be documented.