Die Verwendung alkoholischer Lösungen bei der flammenphotometrischen Analyse

Zusammenfassung Wenn man die Genauigkeit und Empfindlichkeit der flammenphotometrischen Bestimmung von Calcium und Magnesium bei der Verwendung einfacher Flammenphotometer besonders steigern will, so eignen sich hierzu die alkoholischen Lösungen von einigen bestimmten Salzen dieser Metalle. So tritt mit steigenden Verbrennungswärmen der homologen Alkohole: Methyl-, Äthyl-, Propyl-, Butyl-, Amylalkohol usw. eine Steigerung der Linienemission ein. Für Calcium und Magnesium ergibt sich in amylalkoholischer Lösung gegenüber Wasser eine Erhöhung des Photostromes des Selenmeßinstrumentes um das Dreifache. Da Ca(NO₃)₂ und CaCl₂, sowie Mg(NO₃)₂, MgCl₂ und MgSO₄ bis zu großen Konzentrationen in Amylalkohol löslich sind, eignen sich diese Salze für die flammenphotometrische Bestimmung von Calcium bzw. Magnesium. Zu den Messungen wird ein Flammenphotometer von Dr. Lange, Berlin, verwendet, das für das Versprühen brennbarer Probeflüssigkeiten umgebaut wurde. Bisher wurde diese Methode zur Bestimmung kleinster Mengen von Ca(NO₃)₂ in technischen Produkten mit großem Erfolg verwendet. Die Reproduzierbarkeit liegt bis 1,00% bei ± 0,02% Ca(NO₃)₂. Für Magnesium liegen die Verhältnisse etwas ungünstiger.

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Summary If it is desired to increase considerably the accuracy and sensitivity of the flame photometric determination of calcium and magnesium when a simple flame photometer is used, it is well to use alcohol solutions of several particular salts of these metals. Thus, with increasing heats of combustion of the homologous alcohols: methyl-, ethyl-, propyl-, butyl-, amyl alcohol, etc., there is an increase of the line emission. For calcium and magnesium, there is a threefold increase of the photocurrent of the selenium instrument when amyl alcohol is used as solvent rather than water. Since calcium nitrate and chloride and likewise magnesium nitrate, chloride, and sulfate are soluble to high concentrations in amyl alcohol, these salts are suitable for the flame photometric determination of these metals. A flame photometer by Dr. Lange of Berlin was employed for the measurements; it was remodeled for the spraying of combustible liquid samples. Up to the present, this method has been employed with great success for determining extremely small amounts of calcium nitrate in technical products. The reproducibility is up to 1% at ± 0.02% calcium nitrate. The results are not so favorable in the case of magnesium.

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Résumé Si l'on désire augmenter beaucoup la sensibilité et la précision de la détermination par photométrie de flamme du calcium et du magnésium à l'aide d'un photomètre à flamme simple, il est commode d'employer des solutions alcooliques de certains sels de ces métaux. Ainsi l'augmentation des chaleurs de combustion des alcools homologues: méthylique, éthylique, propylique, butylique, amylique etc. entraine une augmentation dans l'émission spectrale. Pour le calcium et le magnésium le courant photoélectrique d'une cellule au sélénium est triplé quand on emploie comme solvant l'alcool amylique à la place de l'eau. Puisque le nitrate de calcium, ie chlorure de magnésium ainsi que le sulfate et le nitrate de ce métal, sont très solubles dans l'alcool amylique, ces sels conviennent pour déterminer ces métaux par photométrie de flamme. On a employé pour ces mesures un photomètre de flamme du Dr. Lange de Berlin. Il était modifié pour permettre la pulvérisation de liquides combustibles. Jusqu'à présent cette méthode a été employée avec succès pour la détermination de très petites quantités de nitrate de calcium dans des produits techniques. Jusqu'à 1% la reproductibilité est ± 0,02%. Les résultats ne sont pas aussi favorables dans le cas du magnésium.

     

Non-reactive metal/semiconductor interfaces: a combined AES,AFM andPAC study

Thin In films on Ge(100), Si(100) andSi(111) are investigated using Auger-electron spectroscopy (AES), atomic force microscopy (AFM) andperturbed -angular correlation (PAC) spectroscopy, respectively. The growth mode of the metal films is characterized by in situ AES measurements, indicating distinct differences between the different substrate surfaces. Additional AFM investigations are used to monitor the film topography at higher metal coverage. Finally, the local crystalline structure of the films is studied by the PAC technique.     

The reaction of allenylsilanes with α,β-unsaturated acylsilanes: new annulation approaches to five and six-membered carbocyclic compounds

The reaction of α,β-unsaturated acylsilanes with allenylsilanes can be directed to produce either five or six-membered carbocyclic compounds.     

Projection between basis sets: A means of defining the electronic structure of functional subunits

The general problem of the transfer of the representation of a set of orthonormal functions from one basis to a different, nonequivalent one is considered and specialized to a matrix formulation convenient for use in molecular electronic structure calculations. A procedure is suggested for treating problems where the transfer of representation breaks into a subset of most interest and one of less interest as for example the occupied and virtual orbitals of a Hartree-Fock SCF calculation. These techniques are then applied to obtain a representation of a methyl group from an SCF wave function for methane.     

Q value and half-lives for the double-β-decay nuclide 110Pd

The 110Pd double-β decay Q value was measured with the Penning-trap mass spectrometer ISOLTRAP to be Q=2017.85(64) keV. This value shifted by 14 keV compared with the literature value and is 17 times more precise, resulting in new phase-space factors for the two-neutrino and neutrinoless decay modes. In addition a new set of the relevant matrix elements has been calculated. The expected half-life of the two-neutrino mode was reevaluated as 1.5(6)×10(20) yr. With its high natural abundance, the new results reveal 110Pd to be an excellent candidate for double-β decay studies.     

Growth and melting behaviour of thin in films on Ge(100)

Growth and melting behaviour of thin indium films on Ge(100) have been investigated by Auger-electron spectroscopy (AES), atomic force microscopy (AFM) and perturbed angular correlation (PAC) spectroscopy, respectively. At room temperature inidium is found to grow in three-dimensional islands even at submonolayer coverages. A very rough film surface is observed for thicknesses up to 230 ML. The melting behaviour of such films has been studied by PAC. A reduction of the melting temperature T _m as well as a strong supercooling of the films is observed. The electric field gradient for ¹¹¹In(¹¹¹Cd) in the indium islands is determined as a function of temperature and is used to monitor the local crystalline order of the films up to temperatures just below the melting point.     

Geometric phase and nonadiabatic effects in an electronic harmonic oscillator

Steering a quantum harmonic oscillator state along cyclic trajectories leads to a path-dependent geometric phase. Here we describe its experimental observation in an electronic harmonic oscillator. We use a superconducting qubit as a nonlinear probe of the phase, which is otherwise unobservable due to the linearity of the oscillator. We show that the geometric phase is, for a variety of cyclic paths, proportional to the area enclosed in the quadrature plane. At the transition to the nonadiabatic regime, we study corrections to the phase and dephasing of the qubit caused by qubit-resonator entanglement. In particular, we identify parameters for which this dephasing mechanism is negligible even in the nonadiabatic regime. The demonstrated controllability makes our system a versatile tool to study geometric phases in open quantum systems and to investigate their potential for quantum information processing.