Die automatisierte Bestimmung von Kohlenstoff und Wasserstoff. IV

Zusammenfassung Ein Gemisch von-Naphthylisocyanat mit etwa 6 1,4-Diazabicyklo-[2,2,2]-oktan (10–15 ml) reagiert quantitativ und sofort mit mg-Mengen Wasser unter Bildung von Kohlendioxid, das anschließend automatisch titriert wird. Wassermengen von etwa 0,3–3 mg lassen sich in etwa 8 min mit einer Standardabweichung von 0,8% rel. bestimmen.

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The automatic determination of carbon and hydrogen. IV

Summary A mixture of about 10–15 ml of-naphthylisocyanate with about 6%. 1,4-diazabicyclo [2,2,2]-octane reacts instantaneously and quantitatively with water in mg quantities. The resulting carbon dioxide is automatically titrated. Amounts of water of about 0.3–3 mg were determined within 8 min. with a standard deviation of 0.8% rel.

     

Prepolymer film growth by adsorption out of solution on silicon and aluminium

A cyanurate prepolymer has been applied to smooth silicon wafers or to distinctly structured aluminium coatings. The surface composition of the substrates has been investigated by X-ray Photoelectron Spectroscopy (XPS), Auger Electron Spectroscopy (AES) and ellipsometry. The application methods, spin coating and dip coating represent adsorption by a technical process exerting significant shear stresses or nearly equilibrated conditions, respectively. The mean tickness of the prepolymer film has been adjusted by variation of the concentration of the solution and checked by ellipsometry. Atomic Force Microscopy (AFM) monitored the development of the respective film morphologies of all 4 systems (silicon/aluminium, spin/dip coating) in the mean film thickness range from 1 to 50 nm.     

Blotting from PhastGel media after horizontal sodium dodecyl sulfate-polyacrylamide gel electrophoresis

An improved procedure, "thermoblotting", is described for transferring proteins by diffusion from PhastGel Gradient media to an immobilizing matrix after horizontal sodium dodecyl sulfate-polyacrylamide gel electrophoresis. After electrophoresis the gels were left on the separation bed of PhastSystem, the blotting matrix was applied and a transfer temperature was selected between 5-70 degrees C. An experimental series at fixed diffusion times showed that the transfer yield was significantly increased with temperature. The evaluation was done visually after staining of the blots with colloidal gold. An evaluation study comparing nitrocellulose, nylon, and polyvinylidenedifluoride of different pore sizes is also reported. Finally, the transfer efficiencies for 125I-labelled bovine serum albumin and soybean trypsin inhibitor were estimated using four different blotting procedures: two diffusion blotting techniques and two electrophoretic blotting techniques (tank vs. semi-dry).     

Die Kristallstruktur von Ru2Si3

The crystal structure of Ru₂Si₃ has been refined by leastsquares using three-dimensional X-ray data from a twinned crystal (1355 reflections,R=5.8%). Ru₂Si₃ is isostructural with Ru₂Ge₃ and like this compound a member of the Mn₁₁Si₁₉ structure family. The lattice parameters of the orthorhombic unit cell (Pnca—D ₁₄ ^2h ) are:a=5.530 (1),b=11.060 (2) andc=8.952 (2) Å.

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Mit 1 Abbildung     

Über die Konfiguration des Prolins im Ergotamin

It is well known that in the ergot alkaloids of the peptide type the proline appears in thel-configuration. Different methods of acid hydrolysis may lead to various cleavage products; hydrolysis by HCl yieldsd-proline, on the other hand hydrolytic cleavage by means of strongly acid cation exchange resin preserved the orginall-configuration.

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Teilveröffentlichung der Dissertation vonH. Kolassa, Univ. Wien, 1973.     

Raman and cathodoluminescence spectroscopic investigations on Permian fossil wood from Chemnitz--a contribution to the study of the permineralisation process

Samples of different three-dimensionally preserved fossil plants (Medullosa sp., Dadoxylon sp., Calamodendron striatum, Psaronius sp.) from the Lower Permian petrified forest of Chemnitz were examined with regard to their chemical composition and structural order. Raman spectroscopy and cathodoluminescence microscopy are shown to be powerful tools for such investigations. Silicified wood from Chemnitz-Hilbersdorf generally shows yellow cathodoluminescence (CL) of the cell walls and only weak yellow-brownish CL of the cell lumina. By time-resolved cathodoluminescence spectroscopy, a secondary mineralisation of hydrothermal origin was recognized. The latter is shown by short-lived blue CL at the cell walls extinguishing the yellow signal. Therefore, after the primary silicification step a secondary mineralisation step initiated by hydrothermal processes, seems to have taken place at probably slightly higher temperatures. The resulting silica matrix consists of phanerocrystalline and microcrystalline alpha-quartz as well as microcrystalline moganite, both partially associated with iron oxides. Dadoxylon sp. is a prominent example for parallel permineralisation by alpha-quartz and fluorspar, which is outstanding for the Chemnitz Petrified Forest. CL on this samples shows parallel silicification and fluoritisation, followed by infiltration of iron oxides. Permineralised samples show very low percentage of original organic remains. The seed fern Medullosa, for example, shows dispersed carbon, which is mainly restricted to the centres of the typical star-shaped vascular bundles. Raman spectroscopy revealed that these carbonaceous particles are of an anthracite structure. For experimental confirmation coal samples of different rank, especially anthracite from different geological times and localities, were studied by means of Raman spectroscopy. The remaining pith of the vascular bundles is white-coloured and consists of alpha-quartz and moganite, whereas surrounding tracheides exhibit white and reddish coloured parts. The reddish parts, mainly found in the rays, additionally contain alpha-Fe2O3 and Fe3O4 among the SiO2 polymorphs of alpha-quartz and moganite. Sometimes iron oxides could have dominated permineralisation processes as the peak intensities of distinct parts of the samples suggest.     

The degradation of bentazone and chlorotoluron in aqueous solutions by gamma radiation. Biodegradability and toxicity /to Tubifex tubifex/ of radiolysis products

Model aqueous solutions of bentazone and chlorotoluron /herbicide concentration=200 mg.l^–1/ were irradiated with and without simultaneous aeration by -doses in the range 0–52.8 kGy. The degradation of herbicides was studied by UV spectroscopy and chronometric method of herbicide residues determination. The effect of radiation on the biodegradability of bentazone and chlorotoluron solutions were evaluated on the basis of BOD₅/COD ratio determination and toxicity of nondiluted model solutions irradiated by doses in the given range to worms Tubifex tubifex was determined.     

Microwave heated vapor-phase digestion method for biological sample materials

A microwave heated, vapor-phase nitric acid-hydrogen peroxide digestion method for pulverized, biological sample materials was developed. Sample masses up to 200 mg were digested using calibrated quartz inserts inside first generation type, low-pressure, Teflon-PFA microwave vessels. In the first step, samples were digested in the vapor-phase for 80 min using a progressive heating pattern. Three mL of 70% nitric acid and 0.5 mL of 30% hydrogen peroxide were used as digestion reagents. In the second step, the small residue left after first step digestion was dissolved in 1.4% nitric acid or additionally with 0.5% hydrofluoric acid by heating for 15 min. The digestion method was optimized using pike (Esox lucius) muscle as a test material. The method was further optimized using three certified reference materials. Ca, Cu, Fe, Mg and Zn were determined from NIST-SRM 1577a bovine liver by ICP-AES. Cr and Ni were determined from NIST-SRM 8433 corn bran and NRCC DOLT-2 dogfish liver by GFAAS. For all elements the values obtained were close or within certified limits. Spike recoveries were between 96 to 107%. Digestion efficiency ranged from 91 to 99%.     

Determination of chlorine and pentachlorophenol in wood

Chlorine in wood was determined in connection with the development of a reference material (RM) of pentachlorophenol (PCP) in wood. The element was determined by photon activation analysis (PAA) using bremsstrahlung of 19 MeV electrons from an electron linear accelerator. The initial overall Cl content as well as the Cl remaining after extraction with methanol and subsequent extraction with water were determined. Moreover, the PCP fractions in the organic and in the aqueous extracts were analyzed by gas chromatography (GC). The results show that at least three quarters of the overall chlorine is bound in PCP and that PCP can be extracted to a high degree.     

Untersuchungen über den Phytolgehalt von Pflanzen

Zusammenfassung Es wurde festgestellt, daß der Phytolgehalt von Blättern der Roßkastanie (Aesculus hippocastanum) im Laufe der Vegetationsperiode von praktisch Null in den Knospen mit der Ausbildung der Blätter rasch zum Maximalwert ansteigt. Es sind keine Anhaltspunkte dafür gegeben, daß wesentliche Phytolmengen außer den im Chlorophyll gebundenen in den Knospen oder grünen Blättern vorhanden sind. Dagegen bleibt bei der herbstlichen Laubverfärbung der Phytolgehalt noch erhalten und nimmt erst mit der Verrottung der abgefallenen Blätter ab.Blätter und Stengel von Feuerbohnen (Phaseolus multiflorus), die in Dunkelheit gezogen wurden und praktisch chlorophyllfrei waren, enthielten auch kein Phytol.