Über die Mannigfaltigkeit ebener Kurven mit Singularitäten

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Darstellung und eigenschaften von und reaktionen mit metallhaltigen heterocyclen: XXXIII. Synthese und kristallstruktur von (μ3-thio)(μ3-organophosphido)tris(tricarbonyleisen)-(2Fe-Fe)-komplexen

The cluster compounds (μ₃-S)(μ₃-PR)Fe₃(CO)₉ are obtained by reaction of the dichloroorganylphosphane sulphides RP(S)Cl₂ (R = CH₃, 4-CH₃OC₆H₄, C₆H₅) with Na₂[Fe(CO)₄] in ether under cleavage of the PS bond. On the basis of X-ray crystallographic determinations the iron clusters crystallize for R = 4-CH₃OC₆H₄ and C₆H₅ in the monoclinic and triclinic space group C2/c and P$\text{1}$ with Z = 8 and 4, respectively.     

Combined ultraviolet-fluorescence detection in high-pressure liquid chromatography of pharmaceuticals.

The use of combined UV-fluorescence detection for the evaluation of incompletely resolved compounds and trace components in the presence of large quantities of major components is described, analysis for thioridazine and some of its oxidation products by high-pressure liquid chromatography being chosen as a practical example. Mesoridazine and the ring oxide of thioridazine have been determined quantitatively with relative standard deviations (n = 6) of 2.0 and 3.6%, respectively, at concentrations below 0.1 mug per injection. Resolution of the two components is difficult and, in this instance, unnecessary. By a similar approach, it was possible to determine the highly fluoresecent sulforidazine at a concentration of 0.4% of the thioridazine with 6.2 mug of thioridazine injected. A relative standard deviation of 5% was attainable at this concentration. Fluorescence detection limits for mesoridazine and sulforidazine at a signal-to-noise ratio of 4:1 are between 5 and 10 ng per injection; this corresponds to about 0.1% of the active substance for the above example.     

Application of the laser microprobe mass analyzer (LAMMA) to qualitative and quantitative single cell analysis

The laser microprobe mass analyzer (LAMMA ) is a new type of analytical instrument. It is a combination of a laser microscope with a time-of-flight (TOF ) mass spectrometer. By focusing an UV pulse laser beam onto the specimen positive and negative atomic and molecular ions are formed which are detected by the TOF mass analyzer. The detection limits reach 10^–20 g for some elements in an excited sample volume of 10^–13 cm³. With the aim of finding out whether the LAMMA instrument is capable of quantitative measurements on very small biological samples the ²³Na⁺ and ³⁹K⁺ contents of single mycobacterial cells (M. tuberculosis H 37 Ra) were measured and the results were compared with those obtained from “integral” methods (AAS, NAA , tracer). Furthermore, the influence of different temperatures applied during the washing procedure of the bacteria on the distribution of the Na⁺/K⁺ ratio within the cell population was investigated. First attempts to trace isonicotinic acid hydrazide (INH) in bacteria were made by comparison of the LAMMA spectra of INH treated and untreated cells.     

Stratifizierung im Hilbertschema II: Flächen mit gewöhnlichen Singularitäten

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