Über eine Kombinationsmöglichkeit der Gas-Chromatographie mit der Flammenphotometrie für den Chlornachweis

A gas-chromatograph is combined with a filter flame-photometer, specific only for chlorine. It is shown that the chlorine containing peaks of the GC can be identified by this combination. The resolving power of the GC combined with the photometer is improved. The detection limit for Cl is 0.003 μg. The precision of the Cl-peaks is ±2.2%. Quantitative measurements of the Cl content of the GC fractions are possible after calibration.     

The decay of 31 sec98Zr, 2.9 sec98Nb and 51 min98Nb

TheΒ- andγ-radiations of⁹⁸Zr and^{98m, g} Nb have been investigated employing scintillation and semiconductor spectrometers and coincidence techniques. Sources of⁹⁸Nb were produced by the⁹⁸Mo(n, p)⁹⁸Nb reaction, sources of⁹⁸Zr by fission of²³⁵U with thermal neutrons applying chemical separations. For⁹⁸Zr, a half-life of 30.7±0.4 sec and aQ _β-value of 2.3±0.2 MeV were obtained, for the⁹⁸Nb isomers, half-lives of 2.86±0.06 sec and 51.3±0.4 min, andQ _β-values of 4.8±0.2 MeV and 4.5±0.2 MeV, respectively. Noγ-rays were observed in the decay of⁹⁸Zr. The decay of 2.9 sec⁹⁸Nb was found to involve 11γ-ray transitions. In the decay of 51 min⁹⁸Nb, 54γ-transitions were detected. Spin and parity of 1⁺ and 4^? were deduced for the isomeric states of⁹⁸Nb.     

Mechanism of isotope exchange reaction between methane and deuterium

The rate of CH₄ disappearance in a shock-heated CH₄:D₂:Ar = 9.70:9.86:80.44 mixture was monitored by coincidence absorption of the 2948 cm^?1 He-Ne laser line over the shockfront temperature range of 1900–2300K. Comparison with CH₄ pyrolysis results by means of computer simulations suggested that atom and free radical chains are responsible for the homogeneous D/H exchange reaction on CH₄. Additional simulations for the experimental conditions of previous single-pulse shock tube experiments led to the recognition of a high sensitivity of the exchange rate to trace amounts of hydrocarbon impurity and to the dissociation rate of CH₄.     

Flammenspektrophotometrischer Schnelltest zum Nachweis von organischen Chlorverbindungen, insbesondere von chlorhaltigen Insecticiden

Zusammenfassung Es wird eine einfache, schnelle, empfindliche und spezifische Methode zum flammenphotometrischen Nachweis organischer Chlorverbindungen als Indiumchlorid, insbesondere von chlorhaltigen Insecticiden, angegeben. Eine Anwendungsmöglichkeit dieser Methode wird beim Insecticidnachweis in Butter ausgeführt.

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The residue analysis of organic chlorine by flame spectrophotometry for the detection of chlorinated pesticides

A simple, quick, sensitive and specific flamephotometric method for the estimation of chlorinated pesticides as indium chloride is described. As an example the analysis of pesticides in butter is demonstrated.

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Unterstützt mit Mitteln der Deutschen Forschungsgemeinschaft. — Herrn Professor Dr. E. Asmus zum 60. Geburtstag gewidmet.

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Für wertvolle Literaturhinweise danken wir den Herren Professoren Janoschek in Gie\en, Kiermeier in Weihenstephan und Lembke in Kiel, ferner den Herren Privatdozenten Dr. K. Lang und Dr. W. Buss in Gie\en. Herrn Dr. P. Post in Gie\en danken wir für die überlassung von Insecticid-Reinstsubstanzen.     

Sättigungseffekte und Linienaufspaltung bei der stimulierten Resonanz-Raman-Streuung

Saturation Effects and Line Splitting of the Stimulated Resonance Raman Scattering The gain of the stimulated resonance Raman scattering (SRRS) is calculated for the case of any sharp resonance. It is shown that under steady-state conditions for longitudinal excitation in direction of the cell the saturation of the absorption is a necessary condition to find a sufficient large gain. Therefore, in the case of a Franck-Condon excitation the SRRS with an excited initial level is only possible, whereas for a O—O-excitation the SRRS with the ground or an excited state as initial state is equally probable. Changing of the population by stimulated fluorescence does not influence this assertion.     

Entwicklung von spektroskopischen Detektoren für die Hochdruck-Flüssigkeits-Chromatographie (HPLC) zum Nachweis von Cl,Br und J

Cl-, Br- and J-specific detectors to be used at the end of a high pressure liquid chromatograph (HPLC) are developed by help of flame spectroscopic methods. The intensities of the band spectra of InCl, InBr and InJ are taken as measure for the Cl, Br and J contents in the HPLC fractions. The mode of operation of the Gilbert indium-burner with a separated H₂-pressed air flame entails the problem that the continuous liquid output of the HPLC must be converted into a continuous gaseous output. During this conversion the organic parts of the eluent, for example methanol in a mixture of methanol-water has to be removed by evaporation. The mentioned conversion and, evaporation is fulfilled by a special transportation and evaporation device. In developing such devices the achieved detection limits (theory given by H. Kaiser) is a valuable aid to compare their efficiencies.