Macroscopic Isotope Separation of 13C by a CO2 Laser

By photochemical dissociation of the rare carbon isotope component of CHClF₂ by means of a CO₂ laser with an average power of 150 W, Q-switched at 10 kHz, we have demonstrated the separation of more than 1 mol of ¹³C, enriched to 50% (2 mol of total carbon). It is contained in about 1 mol (101 g) of the product C₂F₄. The total throughput of the starting material was 29 kg. The experiment was run day and night for 2 weeks, almost only controlled by a computer. We obtained production rates of 5 mmol/h, corresponding to about 0.5 kg ¹³C per year.     

Chemische Dosimetrie ionisierender Strahlung

Es wird über die Aufgaben der Isocommerz GmbH als Leiteinrichtung berichtet. Dabei werden Angaben über die Anwendungsmöglichkeiten von Isotopen und ihren volkswirtschaftlichen Nutzen gemacht.     

The any particle molecular orbital approach: A short review of the theory and applications

The any particle molecular orbital (APMO) approach extends regular electronic structure methods to study atomic and molecular systems in which electrons and other particles are treated simultaneously as quantum waves. A number of electronic structure methodologies have been extended under the APMO framework and applied to investigate nuclear quantum effects including isotope effects and nuclear delocalization and to calculate proton binding energies and affinities. In addition, APMO methodologies have been employed to analyze physical and chemical properties of atomic and molecular systems containing exotic subatomic particles.     

Bestimmung des Verhältnisses der 85Sr-Ausbeuten für die Kernreaktionen Rb (d, 2n) 85mSr → 85Sr und Rb (d, 2n) 85Sr in einem dicken Target

Es wird die Kernreaktion Rb (d, 2n)⁸⁵Sr beschrieben, die zur Erzeugung von ⁸⁵Sr verwendet wird. Für die Auysbeute von ⁸³Sr in einem dicken RbCl-Target bei der Deuteronenenergie E_d=13 MeV ergibt sich 14,1 μCi/μAh. Das Radionuklid ⁸³Sr entsteht sowhol über den Isomerkern ^85mSr als auch durch eine direkte Kernreaktion Rb (d, 2n) ⁸³Sr. In der Arbeit sind Aktivitätsfunktionen für ^83mSr und ⁸⁵Sr angegeben, bezogen auf 1 μA des Deuteronenstromes, in Abhängigkeit von der Bestrahlungszeit bis 20 h und von der Zerfallszeit bis 15 h. Die Bildung von ⁸⁵Sr ūber ^85mSr betrāgt 64%, die direkte Entstehung von ⁸⁵Sr 36% von der Gesamtausbeute.     

Impact of Deuteration and Temperature on Furan Ring Dynamics

Despite significant progress in conformational analysis of cyclic molecules, the number of computational studies is still limited while most of that available in the literature data have been obtained long time ago with outdated methods. In present research, we have studied temperature driven conformational changes of the furan ring at three different temperatures. Additionally, the effect of deuteration on the ring dynamics is discussed; in addition, the aromaticity indices following the Bird and HOMA schemes are computed along all trajectories. Our ab initio molecular dynamic simulations revealed that deuteration has changed the furan ring dynamics and the obvious consequences; in addition, the shape and size of molecule are expected to be different.     

A Regioselectively Labelled Reagent for the Koenigs-Knorr Synthesis of Deuterated Drug Conjugates

A reaction scheme is presented which allows for the first synthesis of a specifically ²H-labelled α-bromo glucuronic ester. With this Koenigs-Knorr reagent analogue, labelled drug conjugates become facilely accessible.     

Bias reduction in the quantitative analysis of a target analyte present in a limited quantity in human plasma using dual-mode heart-cutting two-dimensional liquid chromatography coupled with isotope dilution mass spectrometry

Dual-mode heart-cutting two-dimensional liquid chromatography (DMHC 2D-LC) was applied to isotope dilution mass spectrometry (IDMS) to reduce the bias in the quantitative analysis of a target analyte present in a limited quantity in human plasma. Based on a Waters I-Class LC system, the DMHC 2D-LC system was operated in one- and two-dimensional modes to facilitate the determination of heart-cutting time and the efficient trapping of the target LC eluate. Experiments to determine the feasibility of coupling with IDMS were performed with triple quadrupole mass spectrometry using folic acid standards and/or ¹³C₅-folic acid. To validate the performance of the DMHC 2D-LC/IDMS system on a complex sample, human plasma was analyzed for folic acid and the result was compared with that obtained using conventional single-column LC. The total run time of the DMHC 2D-LC system was 20 min, the same as that of the single-column LC system. The peak profile of the spiked ¹³C₅-folic acid obtained with single-column LC/MS was affected by matrix effects, but resolved with DMHC 2D-LC/MS, thus improving the accuracy of the analysis. The DMHC 2D-LC/IDMS system showed reliable performance in analyzing the target analyte in human plasma, eliminating matrix effects and saving analysis time.     

О методе иолучсния F18 (без носителя) из облученного лития

Es wird über Untersuchungen zur quantitativen Bestimmung von Rubidium, Strontium und Kupfer im ppm- bzw. ppb- Bereich mit Hilfe der Isotopenverdünnungsanalyse mit stabilen Nukliden berichtet. Die erreichten Nachweisgrenzen und Standardabweichungen werden angegeben. Die Anwendung der Analysenmethode bei der Untersuchung von hochreinen Materialien und zur Altersdatierung von Gesteinen wird erläutert.