Purification of americium from bulk quantities of plutonium loading effluent using trilaurylamine

Four litres of Am solution containing 81.5 mg/l Am and 0.6 mg/l Pu could be purified by a two-step procedure involving solvent extraction and extraction chromatography with trilaurylamine. The final product contained a maximum concentration of 9 g/l Pu.     

Kinetic dual standard additions method for the determination of two mutually interfering analytes: Molybdate and tungstate

A kinetic dual standard additions method for determination of two mutually interfering analytes is proposed. The deviations of absorbance from additivity in kinetic systems, caused by synergistic effects of catalysts, are compensated with the defined synergistic catalytic coefficient. The hydrogen peroxide-iodide kinetic reaction catalysed by molybdate and tungstate was studied with the stopped-flow injection technique and the conditions for simultaneous determination of Mo and W established. The molybdenum and tungsten contents in different samples were determined with recoveries of 97.6 102.1% and 96.9 98.6%, and relative standard deviations of 2.3 3.4% and 1.6 2.6%, respectively.     

Simple screening method for the fast determination of clenbuterol in animal feeds

Summary A simple method for the determination of clenbuterol is described. It is extracted from the sample at pH 3 and then at pH 11, followed by partitioning the analyte into water at pH 3 and reextraction into ethyl acetate at pH 9. Clenbuterol is oxidized with KMnO₄ to clenbuteron for GC-determination. Recoveries for 0.01– 1.0 mg/kg were between 70% and 110% (standard deviation ±14%, n = 18).

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Eine einfache Screening-Methode zur schnellen Bestimmung von Clenbuterol in tierischen Futtermitteln

     

Strategies to vectorize conventional SCF-Cl algorithms

Recent high-performance computers, especially supercomputers, achieve very high-speed operations but bring about serious I/O problems in quantum chemical computations. Strategies to vectorize conventional SCF-CI algorithms are discussed relating to the I/O problems. The conventional SCF-CI algorithm which is proposed here reduces I/O processing by eliminating all sorting routines and redundant integral files and generates directly nonzero and nonredundant PK integrals with a vectorizable canonically-ordered list. The new implementation has been undertaken and successfully realized as a program system named GSCF3. The vector to scalar acceleration rate of GSCF3 on the HITAC S-810 are as follows: 2.5 5 in the AO integral evaluation, 5 12 in the SCF calculation, 15 30 in the four-index integral transformation, 10 20 in the CI matrix diagonalization, and overall 510 through SCF-CI.     

Über einige Komplexboride von Übergangsmetallen

Zusammenfassung Dreistofflegierungen in dem Kombinationen {Mo, W}-{Fe, Co, Ni}-B; {V, Nb, Ta, Mo, W}-B-Al werden vornehmlich auf die Existenz von Komplexboriden hin untersucht. Die isotypen Phasen Mo₂CoB₂, Mo₂NiB₂, W₂FeB₂, W₂CoB₂ und W₂NiB₂ sind strukturell mit Mo₂FeB₂ verwandt, aber doch von dieser Phase verschieden. Gefunden werden außerdem die isotypen Phasen MoCoB und WCoB. Das Problem der -Phase wird diskutiert. In manchen Fällen tritt ein Zwischenzustand auf, der vermutlich durch Stapelfehler einer Unterzelle (c/3 in hexagonaler Aufstellung) hervorgerufen wird. Neben dem Auftreten ternärer Phasen bei Nb-B-Al und Ta-B-Al wird eine ausgeprägte Mischphasenbildung: (Nb, Al)B₂ und (Ta, Al)B₂ beobachtet. Der Dreistoff: Mo-B-Al ist durch die ternäre Phase MoBAl gekennzeichmet, ferner tritt der durch Al stabilisierte CrB-Typ auf (Mo_0,45B_0,50Al_0,05). Die Gleichgewichtsverhältnisse in denT-B-Al-Dreistoffen werden abgeschätzt.

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Alloys of the combinations {Mo, W}-{Fe, Co, Ni}-B, {V, Nb, Ta, Mo, W}-B-Al have been examined with respect to the existence of complex borides. The phases of the approximate formula Mo₂CoB₂, Mo₂NiB₂, W₂FeB₂, W₂CoB₂ and W₂NiB₂ have been found to be isotypic. They do however not correspond to Mo₂FeB₂ having U₃Si₂ structure. Two other complex borides of formula MoCoB and WCoB have been detected having the same crystal structure. The problem of the -phases which partially contain boron will be discussed considering the supposedly occurring stacking faults of a subcell unit (c=c/3 for hexagonal symmetry). Besides formation of ternary compounds for: Nb-B-Al and Ta-B-Al an extended solid solution (Nb, Al)B₂ and (Ta, Al)B₂ has been observed. The Mo-B-Al-system is characterized by the ternary phase of formula MoBAl. Mo-monoboride having CrB-type has been found to be stabilized by a small amount of Al, thus Mo_0,45B_0,50Al_0,05 being formed. The phase equilibria within the ternary systems have been established for the major part.

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Mit 4 Abbildungen     

Donorstärken in 1,2-Dichloräthan

Zusammenfassung Kalorimetrische und spektrophotometrische Untersuchungen über die Donorstärke einer Anzahl nicht-wäßriger Lösungsmittel zeigen, daß die relative Reihung der Donorstärken unabhängig von der Natur des Akzeptors ist. Die Donorreihung lautet gegenüber SbCl₅, Jod und Phenol folgendermaßen: Pyridin > Dimethylsulfoxid > Dimethylacetamid Dimethylformamid > > Trimethylphosphat Diphenylphosphoroxychlorid > Diäthyläther > Aceton > Propandiol-1,2-carbonat > Acetonitril > > Selenoxychlorid Phosphoroxychlorid Benzoylchlorid > > Thionylchlorid > Sulfurylchlorid.

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Calorimetric and spectrophotometric work on the donor strength of various non-aqueous solvents have shown that the relative order of donor strength is independent from the nature of the acceptor. The order of donor strength towards SbCl₅, I₂ and phenole is pyridine > dimethylsulfoxide > dimethylacetamide dimethylformamide > trimethylphosphate diphenylphosphonic chloride > diethyl ether > acetone > propane diol-1,2-carbonate > acetonitrile > selenium oxychloride phosphorus oxychloride benzoyl chloride > thionyl chloride > sulfuryl chloride.

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Mit 1 Abbildung     

Determination of traces of sodium alkylbenzenesulphonate by high-performance liquid chromatography. Application to water

Summary For the trace determination of sodium alkylbenzenesulphonate (ABS) by HPLC the following conditions were employed: Shimadzu ZORBAX SIL Column (5 m, 4.6 mm i.d. x 150 mm) as stationary phase, 0.2% ammoniaethanol (v/v) as mobile phase, UV detector at 225 nm, injection volume 12 l. The chromatograms of ABS were simple and sharp (detection limit of ABS 0.02 g in 12 l of ethanol). The calibration curves of ABS were linear in a concentration range of 0.03 0.3 g in 12 l of ethanol. In the case of linear sodium dodecylbenzenesulphonate positive errors of 1 4% were caused by non-ionic surfactants or laurylsulphate (6 times excess), 10 50% positive errors were caused by 2 6 times excess of household detergents.Standard water samples containing ABS were treated with a weak base anion-exchange resin, the adsorbed ABS were eluted, and then determined either by HPLC or by the methylene blue spectrophotometric method. Recoveries of ABS in water were about 92 107% by HPLC.

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Bestimmung von Spuren Natriumalkylbenzolsulfonat mit Hilfe der HPLC. Anwendung auf Wasser

Zusammenfassung Für die Spurenbestimmung von Natriumalkylbenzolsulfonat (ABS) durch HPLC werden die folgenden Bedingungen empfohlen:Shimadzu ZORBAX SIL (5 m, 4,6 mm x 150 mm) als stationäre Phase, 0,2% Ammoniak/Ethanol als mobile Phase, UV-Detektor bei 225 nm, Injektionsvolumen 12 l. Die erhaltenen Chromatogramme sind einfach und scharf (Nachweisgrenze 0,02 g in 12 ml Ethanol). Die Eichkurven sind im Konzentrationsbereich von 0,03–0,3 g in 12 l Ethanol linear. Im Falle des linearen Natriumdodecylbenzolsulfonats werden bei Anwesenheit von nicht-ionischen oberflächenaktiven Substanzen oder von Laurylsulfat in 6fachem Überschuß positiver Fehler von 1–4% erhalten; bei 2–6fachem Überschuß von Haushaltswaschmitteln ergeben sich positive Fehler von 10–50%.Standard-Wasserproben werden zunächst einer Behandlung mit einem Anionenaustauscher unterzogen, die adsorbierten ABS eluiert und durch HPLC oder nach der Methylenblaumethode analysiert. Wiederfindungsraten liegen bei 92–107%.

     

On the use of a dead-time meter for pile-up corrections

Correction for pile-up losses in the amplifier is possible by the dead-time fraction indicator of the ADC in case of long-lived radionuclides. If the dead-time meter has been calibrated, an accuracy of 1.5% is feasible up to a dead-time fraction of 25%. The precision decreases from 1.5% at 10% dead-time fraction to 3% at a deadtime fraction of 30%.     

Study of the absorption spectra of the 4f electron transition of the Nd and Er complexes with 2-isobutylformyl-1,3-dione-indane in the presence of TX-100 and its analytical application

The absorption spectra of 4f electron transitions of the systems of neodymium and erbium with 2-isobutylformyl-1,3-dione-indane and TX-100 have been studied by normal and derivative spectrophotometry. Their molar absorptivities at the maximum absorption bands are about 7.2 (at 571 nm) times greater for neodymium and 13.1 (at 519 nm) times greater for erbium than those in the absence of the complexing agents. Use of second derivative spectra both eliminates the interference from other rare earths and increases the sensitivity from neodymium and erbium. Beers law is obeyed from 020 g/ml for neodymium and 025 g/ml for erbium. The relative standard deviations are 1.2% and 1.6% for 5.0 g/ml of neodymium and 8.0 g/ml of erbium, respectively. The detection limits (signal-to-noise ratio=2) are 0.14 g/ml and 0.20 g/ml. A method for the direct determination of neodymium and erbium in rare earth mixtures with good accuracy and selectivity is proposed.     

Catalyzed Determination of Phenylalanine with a Mimic Enzyme Constructed of β-Cyclodextrain Derivant

Phenylalanine was catalyzed and determined with mimic phenylalanine oxidase constructed by the reaction of -cyclodextrin (or -CD) and m-carboxyl benzenesulfonyl chloride with iron trichloride in hydrogen peroxide. The method is simple and convenient. The linear range of this method is 0–0.8233 mmol/L, the detection limit is 8.354 mol/L, the RSD is 0.96% (n = 8), and the recovery rate is 95.8–103.5% when used to test an edulcorator (aspartame) sample.     

Tail-end purification of americium from plutonium loading effluents using a mixture of octyl (phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide and tri-N-butyl phosphate

The tail-end purification of Am from Pu loading effluents in 7.5M HNO₃ containing 160 mg l^–1 Am and 1.2 mg l^–1 Pu has been carried out. With 0.2M CMPO+1.2M TBP in dodecane as the extractant and stripping by 0.04M HNO₃+0.05M NaNO₂, the Pu level is brought down to 31.2 g l^–1. When the acidity was reduced to 4.2M HNO₃, one contact with 20% TLA/dodecane and subsequent extraction by a mixture of CMPO and TBP and stripping with 0.04M HNO₃+0.05M NaNO₂ gave Am samples without any detectable amounts of Pu. The recovery of Am was 90% by the first procedure and 98% by the second one.     

Non-Aqueous Capillary Electrophoresis with Indirect Photometric Detection for Direct Analysis of Pb2+, Zn2+ and Cd2+ Ions

A new approach, based on non-aqueous capillary electrophoresis separation and indirect photometric detection, was established for the determination of the transition metal ions Pb²⁺, Zn²⁺ and Cd²⁺. Under optimized conditions, the method produced baseline separation of these three metal ions. The linear range and detection limits were 1050µM, 1.9µM for Cd²⁺; 1050µM, 2.1µM for Zn²⁺; and 20100µM, 3.8µM for Pb²⁺, respectively.     

Experimental investigation on tritium gettering with hydrogen uranyl phosphate (HUP)

At room-temperature and atmospheric pressure, using electrode disks of various sizes, under the action 4 7Vdc eletric field, we gettered tritium gas from 2.2L of air containing (0.15 18.61)×10⁸ Bq of tritium and (3000 12000) ppm of moisture during 50 hours or so the efficiency of gettering tritium was over 95%. Applying liquid scintillation counting method, we measured the tritium in the disks after gettering, and found that the amounts of tritium in the disks were equal to those reduced in the tested tritiated air.     

Electron-impact-induced anisotropic etching of silicon by hydrogen

The etch rate of silicon in a hydrogen low-pressure discharge plasma can be strongly enhanced by electron bombardment, reaching presently up to 1000 Å/min. The etch rate increases linearly with increasing electron current density and hydrogen pressure (range 0.05–0.7 mbar) and decreases with increasing temperature, yielding an activation energy of –4.2 kcal/mole in a temperature range of 80 to 300°C. The etching remains anisotropic within the whole pressure range studied.     

Kinetik der Bindung von Dansylsarkosin (DS) zur Spezifizierung von Humanalbumin (HSA) in Serumkonserven

Zusammenfassung In Spenderserum und handelsüblichen Serumkonserven wurde die Bindung von Dansylsarkosin (DS) an Humanalbumin (HSA) mit Hilfe von stopped-flow-Messungen bestimmt. Die Umlagerung vom instabilen in den stabilen DS-HSA Komplex erfolgt mit einer Halbwertzeit von 3 ms. Die Halbwertzeit der Dissoziation beträgt für alle untersuchten Seren 25 ms. Wegen unterschiedlicher Affinitäten des Anlagerungskomplexes erfolgt die Bindung von DS nach Sterilisation mit -Propiolacton (BPL) und UV-Licht langsamer als ohne Behandlung der Seren.

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Specification of human albumin (HSA) in preserved serum by dansylsarcosine (DS) binding kinetics

Summary Complexation of dansylsarcosine (DS) with human serum albumin (HSA) has been determined by stopped-flow in fresh human serum and commercial available serum. Conversion of the low affinity into the high affinity DS-HSA complex occurs with a half-life of 3 ms. Dissociation half-life was for all investigated seras 25 ms. Due to different affinity constants of the low affinity complex, binding reaction is slower for serum sterilized by -propiolacton and UV-light in comparison with untreated serum.

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Die Arbeit wurde durch die DFG unterstützt     

Recoil reactions of38Cl and128I in some heterocyclic systems

Halogen recoil following /n, / reaction has been studied in some heterocyclic systems. The organic yields are 60% for irradiation as solids: exceptions are dioxanide furoate /34%/ and 5-chloro isatoic anhydride /31%/. As solutions in 11 THF + benzene and 11 HTF+DMSO, these yields are lower by 10% and decrase further when only THF is the solvent. Mass-spectroscopy data revealed the possible fragmentation pattern.     

Reversible Optical Sensor Membrane for Hydrogen Peroxide Using an Immobilized Fluorescent Probe,and its Application to a Glucose Biosensor

An optical sensor for hydrogen peroxide (HP) based on the probe europium tetracycline (EuTc) incorporated into a polyacrylonitrile-co-polyacrylamide polymer matrix is described. Upon optical excitation with 400-nm light, the EuTc in the membrane displays fairly strong fluorescence peaking at 616nm. The fluorescence intensity increases up to 3-fold if the sensor is exposed to solutions containing HP. The effect is reversible and can thus be used for continuous sensing. The largest signal changes with HP are observed at pH levels between 6.5 and 7.5, and the range of the response is between 10 and 300ppm (w/w) of HP, equal to 0.3 to 10mmolL^–1). At concentrations above 0.3% of HP, decomposition of the EuTc in the membrane is observed. The limit of detection is 15ppm (0.45mmolL^–1). The response is fully reversible and rather slow (10min) in both directions, but the reverse response may be accelerated by addition of a reducing agent such as thiosulfate. Alkali ions and most anions remain inert, but phosphate and citrate interfere, as do Cu²⁺ ions, which quench fluorescence. In order to image the spatial distribution of HP concentrations, sensor membranes were placed on the bottom of the wells of a microtiter plate, and their fluorescence was imaged using an LED-based device based on the measurement of the luminescence decay time of EuTc. If glucose oxidase is immobilized on the sensor layer, a glucose sensor is obtained in which the HP sensor acts as the transducer and which can quantify glucose in concentrations between 0.1 and 5mmolL^–1. The limit of detection for glucose is 0.2mmolL^–1.     

Synthesis and stereochemistry of benzo[a]cyclohexano[f]quinolizidines of the 8-aza-D-homoestrane series

A mixture of trans,anti, cis- and cis,anti,cis-quinolizidines in a ratio of 14, respectively, was obtained (in 10% yield) in the thermal condensation of 4-methyl-4-acetylcyclohex-2-en-1-one with 3,4-dihydroisoquinoline.Translated from Khlmiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1662–1668, December, 1981.     

On-stream measurement of heavy water concentration by intermediate neutron moderation

A method of measuring heavy water concentration is described based on intermediate neutron moderation. With a 1.6 g²⁵²Cf neutron source and a BF₃ proportional counter, for 500 ml samples, accuracies of the measurements are within ±0.02 mol% in the concentration range of 0100 mol% with 210 minute counting. To evaluate the practical effectiveness of the method, a model apparatus was built for routine use in laboratory and on-stream measurements. It was successfully applied to observe the substitution process between light water and heavy water in an ion exchange resin tower at a nuclear power station.     

Kerr constants and structure of benzoic acid in dioxane and CCl4

The dipole moment and Kerr effect methods showed that the dimer of benzoic acid has a conformation close to the twist form with a dihedral angle of 10°. The fraction of atomic polarization of the dimer is anomalously high (P_a 50% P_e), and it retains some polarity (DM 0.58 D).A. E. Arbuzov Institute of Organic and Physical Chemistry, Kazan' Scientific Center, Russian Academy of Sciences, 420083 Kazan'. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 5, pp. 1069–1072, May, 1992.