Ma?analytische Bestimmung von Anilin, Monomethylanilin und Mono?thylanilin

Zusammenfassung In der vorliegenden Arbeit wird eine oxydimetrische Bestimmung von Anilin, Monomethylanilin und Monoäthylanilin mit Natriumchlorit empfohlen. Man läßt mit einem Reagensüberschuß umsetzen und titriert den unverbrauchten Rest jodometrisch zurück. Die Methode erlaubt die Bestimmung dieser Amine in sehr kleinen Mengen, und die Ergebnisse sind zufriedenstellend.

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Summary On oxydimetric determination of aniline, monomethylaniline and monoethylaniline with sodium chlorite has been proposed. An excess of the reagent is added to the sample solution and unreacted chlorite is determined by iodometry. Good results have been obtained, even for very small quantities of the amines.

     

Nachweis und photometrische Bestimmung von Dimethylanilin mit Natriumchlorit in Gegenwart von Monomethylanilin und Anilin

Zusammenfassung Es wird eine colorimetrische Methode für die Bestimmung von Dimethylanilin mit Natriumchlorit vorgeschlagen.Die Bestimmung ist empfindlich und gestattet 30–300 g/ml Dimethylanilin zu bestimmen.Das Verfahren ist auch für die Bestimmung von Dimethylanilin in Gegenwart von Anilin und Methylanilin anwendbar.     

Spektrochemische Bestimmung von Spurenelementen in reinem Gold

Zusammenfassung Eine Spektrochemische Methode zur Bestimmung von Spuren der Elemente As, Sb, Fe, Mn, Pb, Ni, Bi, Cu, Pt, Pd, Cd, Rh und Ag in reinem Gold wird beschrieben. Zunächst wird das Gold durch Extraktion aus 3 N HCl mit Methylisobutylketon abgetrennt. Die Verunreinigungselemente werden dann an spektralreinem Graphitpulver mit 4% NaCl und 0,02% Co als Bezugselement adsorbiert und im Wechselstromabreißbogen 3,5 min bei 10 A angeregt. Die Spektren wurden mit einem UV-Spektrograph Q 24 auf ORWO-Spektralplatten Blau Extrahart aufgenommen. Die quantitative Bestimmungsgrenze für Mn, Pt und Ag beträgt 10^–6%, für Fe, Pb, Ni, Bi, Cu, Pd und Rh 10^–5% und für As, Sb und Cd 10^–4%. Die relative Standardabweichung überschreitet nicht 30%.

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Spectrochemical determination of trace elements in pure gold

A spectrochemical method for the determination of traces of As, Sb, Fe, Mn, Pb, Ni, Bi, Cu, Pt, Pd, Cd, Rh and Ag in pure gold is described. The gold is first separated by extraction into methyl isobutyl ketone from 3 N HCl solution and then the trace elements are adsorbed on spectrally pure carbon powder containing 4% NaCl and 0.02% Co as reference standard, and excited in an 10 A a.c. arc for 3.5 min. Emission spectra were recorded on ORWO-Blau Extrahart plates with an UV-spectrograph Q 24. Limits of detection were 10^–6% for Mn, Pt and Ag; 10^–5 % for Fe, Pb, Ni, Bi, Cu, Pd and Rh; 10^–4% for As, Sb and Cd. Relative standard deviation was not exceeding 30%.

     

Theoretical studies on di- and tetra-nuclear Ni pivalate complexes

A combination of DFT calculations and magnetic studies allow structural features of di- and tetra-nuclear nickel pivalate cage complexes to be deduced.     

Uniqueness of the Newton-Wigner position operator

It is shown that the quantum position operator of Newton and Wigner for nonzero-mass systems is uniquely determined if one imposes a quantum manifest covariance condition of the same type as the similar condition of Currie, Jordan, and Sudarshan in the framework of the Hamiltonian formalism.     

Antioxidant activity evaluation by physiologically relevant assays based on haemoglobin peroxidase activity and cytochrome c-induced oxidation of liposomes

Two new protocols for exploring antioxidant-related chemical composition and reactivity are described: one based on a chronometric variation of a haemoglobin ascorbate peroxidase assay and one based on cytochrome c-induced oxidation of lecithin liposomes. Detailed accounts are given on their design, application, critical correlations with established methods and mechanisms. These assays are proposed to be physiologically relevant and bring new information regarding a real sample, both qualitative and quantitative. The well-known assays used for evaluation of antioxidant (re)activity are revisited and compared with these new methods. Extracts of the Hedera helix L. are examined as test case, with focus on seasonal variation and on leaf, fruit and flower with respect to chromatographic, spectroscopic and reactivity properties. According to the set of assays performed, winter are the most antioxidant, followed by summer leaves, and then by flowers and fruits.     

Dynamics of Entropy Production Rate in Two Coupled Bosonic Modes Interacting with a Thermal Reservoir

The Markovian time evolution of the entropy production rate is studied as a measure of irreversibility generated in a bipartite quantum system consisting of two coupled bosonic modes immersed in a common thermal environment. The dynamics of the system is described in the framework of the formalism of the theory of open quantum systems based on completely positive quantum dynamical semigroups, for initial two-mode squeezed thermal states, squeezed vacuum states, thermal states and coherent states. We show that the rate of the entropy production of the initial state and nonequilibrium stationary state, and the time evolution of the rate of entropy production, strongly depend on the parameters of the initial Gaussian state (squeezing parameter and average thermal photon numbers), frequencies of modes, parameters characterising the thermal environment (temperature and dissipation coefficient), and the strength of coupling between the two modes. We also provide a comparison of the behaviour of entropy production rate and Rényi-2 mutual information present in the considered system.     

g‐Engineering in Hybrid Rotaxanes To Create AB and AB2 Electron Spin Systems: EPR Spectroscopic Studies of Weak Interactions between Dissimilar Electron Spin Qubits

Hybrid [2]rotaxanes and pseudorotaxanes are reported where the magnetic interaction between dissimilar spins is controlled to create AB and AB₂ electron spin systems, allowing independent control of weakly interacting S= centers.     

Polyazomethines derived from polynuclear dihydroxyquinones and siloxane diamines

New polyazomethines have been synthesized based on polynuclear dihydroxy quinones (5,8-dihydroxy-1,4-naphthoquinone and 1,4-dihydroxyanthraquinone) and siloxane diamines differing by the siloxane sequence length (1,3-bis(3-aminopropyl)tetramethyldisiloxane and α,ω-bis(3-aminopropyl)oligodimethylsiloxane having about 12 siloxane units/sequence). The structures were verified by spectral analyses. Solubility tests, GPC and viscosity measurements were performed. Some properties of the resulted polymers were investigated by thermal (TGA and DSC), electrical, spectral (UV-Vis) and electrochemical (differential pulse voltammetry) methods.