Trace detection of plutonium by three-step photoionization with a laser system pumped by a copper vapor laser

Laser photoionization has been used to detect trace amounts of plutonium. A high sensitivity and selectivity has been achieved by applying three-step excitation and ionization of the plutonium atoms with high pulse-repetition rates and additional mass determination by time-of-flight measurements. A laser system was developed which consists of a copper vapor laser pumping three dye lasers simultaneously. Samples containing between 10¹⁰ and 10¹² atoms of²³⁹Pu on Re filaments were measured yielding strong resonance signals with maximum ion count rates of several kHz at a vanishingly low background. A detection efficiency of 10^–7 was determined allowing the detection of about 10⁸ plutonium atoms in a sample.This work comprises part of the doctoral dissertation of W. Ruster, to be submitted to Johannes-Gutenberg-Universität, Mainz     

Nuclear Radiation Detected Optical Pumping of neutron-deficient Hg isotopes

The extension of the Nuclear Radiation Detected Optical Pumping method to mass-separated samples of isotopes far off stability is presented for a series of light Hg isotopes produced at the ISOLDE facility at CERN. The isotope under investigation is transferred by an automatic transfer system into the optical pumping apparatus. Zeeman scanning of an isotopically pure Hg spectral lamp is used to reach energetic coincidence with the hyperfine structure components of the 6s ^{2 1} S ₀6s6p ³P₁,λ=2,537 Å resonance line of the investigated isotope and the Hg lamp. The orientation built up by optical pumping is monitored via the asymmetry or anisotropy of the nuclear radiation. Nuclear spins, magnetic moments, electric quadrupole moments and the isotope shifts are obtained for¹⁸¹Hg-¹⁹¹Hg using theβ asymmetry as detector. The extension of the method using theγ anisotropy is discussed and test measurements on¹⁹³Hg are presented. This paper describes the experimental procedure, results, and discussion are given in a following publication.     

HPLC-analyses of plant biomass hydrolysis and fermentation solutions

Summary In this work the analytical separation of biomass hydrolysis and fermentation products is described. Aminobonded phase and ion exchange materials (HPX 87H, HPX 42A, Spherogel Carbohydrate) were used as HPLC stationary phases for the determination of monomeric and oligomeric carbohydrates, carbohydrate degradation and fermentation products. The HPX 42A and the amino-bonded phase columns are especially suitable for the analysis of the gluco oligomers. The HPX 87H column separates the monomeric sugars and their degradation and fermentation products (e.g. furfurals and ethanol) very well. Using the Spherogel Carbohydrate column the lower gluco-oligomers as well as the monomeric sugars and their degradation and fermentation products, can be determined within 35 minutes.     

Analysis of drugs, natural and bioactive compounds containing phenolic groups by capillary electrophoresis coupled to mass spectrometry

This review summarizes the use of capillary electrophoresis (CE) coupled to mass spectrometry (MS) for the analysis of phenolic compounds and its latest developments. Special attention is paid to the different interfaces. The instrumental setups are discussed and demonstrated in a high number of real applications.     

Simultaneous determination of mono- and bivalent cations in environmental chemistry using isocratic ion chromatography

Summary The influence of the pH of the mobile phase ethylenediamine (EDA)/citrate on the retention behaviour of mono- and bivalent cations on a silica based cationexchange stationary phase was studied. Variation of the pH-value was accomplished either by changing the concentration of one component of the eluent or by adding potassium hydroxide or hydrochloric acid to an eluent of fixed composition. The pH range between 2.8 and 3.0 proved to be most suitable for the separation of mono- and bivalent cations. Alkali metals, alkaline earths and transition elements could be separated in a single run. Extending the pH-range up to 5.2 showed the possibility of an additional determination of more strongly retained ions, such as Pb²⁺ or Sr²⁺.

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Simultanbestimmung ein- und zweiwertiger Kationen in der Umweltchemie mit Hilfe der isokratischen Ionen-Chromatographie

     

Analysis of oligomeric and monomeric carbohydrates from hydrothermal degradation of cotton-waste materials using HPLC and GPC

Summary The hydrolysis of different cotton materials under hydrothermal conditions was investigated. For the analysis of the resulting reaction products high-performance liquid chromatography and gel-permeation chromatography were applied. HPLC columns with ion exchange materials as stationary phases (HPX 87P and Shodex S801) enabled the separation of monomeric sugars and degradation products. Oligomeric sugars were analyzed using a gel column (Bio-Gel P-2) as well as a HPLC column (HPX 42A). Through identification of additional reaction products the mass balance of the hydrolysis can be improved and the analysis of the distribution of the oligomeric sugars gives information for the selection of the reaction conditions.