Determination of the spallogenic radionuclides26Al and53Mn in Antarctic meteorites with respect to cosmic ray exposure and terrestrial ages

The spallogenic radionuclides²⁶Al (T=7.18·10⁵ a) and⁵³Mn (T=3.8·10⁶ a) were determined in 11 ordinary chondrites and 7 achondrites from Antarctica by nondestructive coincidence counting techniques and radiochemical neutron activation analysis, respectively. The results are discussed with respect to exposure ages, terrestrial residence times and possible genetic relationships of the meteorites investigated. The high terrestrial ages of some specimens (up to 800 000 years) are of importance for the study of the ice flow in Antarctica.     

Die Bestimmung von53Mn,Welches in Meteoritischem Material Durch Kosmische Strahlung Erzeugt Wurde,mit Hilfe der Neutronenaktivierung

Among a number of stable and unstable nuclides formed in material exposed to cosmic radiation the spallation nuclide⁵³Mn (T=2·10⁶ a) is investigated in meteoritic manganese by combined techniques of neutron activation and advanced γ-spectrometry. The need for an economic use of precious meteorites is so ensured best. Intense neutron bombardment transforms the long-livedK-emitter⁵³Mn into⁵⁴Mn, which is detected by its 0.84 MeV γ-rays. Using the (n,γ) cross section—recently derived byMillard—⁵³Mn-values in the range of 60–600 dpm/kg (10⁻¹¹ g/g) are found in a larger number of iron meteorite samples, which are only 1–3 g in weight. The determination is very specific and under appropriate conditions unaffected by side reactions. The attempt to use the⁴⁴Ti (n,γ)⁴⁵Ti reactions for the analysis of spallogenic titanium failed, because the σ_therm of⁴⁴Ti was found to be unexpectedly low (10 barns). Additionally,⁴⁵Sc was determined after (n,γ) reaction by the⁴⁶Sc γ,γ-cascades.      

Zur emissionsspektralanalytischen Bestimmung von Cu-, Fe- und Pb-Spuren in ZnS-Leuchtstoffen

Zusammenfassung Eine emissionsspektralanalytische Methode wird beschrieben, mit deren Hilfe 3 · 10^–7 bis 3 · 10^–5 g Fe, 2 · 10^–6 bis 3,2 · 10^–6 g Pb und 3 · 10^–8 bis 1 · 10^–5 g Cu pro g ZnS bestimmt werden können.

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Summary An emission spectral analytical method is described by which 3 · 10^–7 to 3 · 10^–5 g iron, 2 · 10^–6 3.2 · 10^–5 g lead, and 3 · 10^–8–1 · 10^–5 g copper per g ZnS can be determined.

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Résumé On décrit une méthode d'analyse spectrale par émission permettant de doser 3 · 10^–7–3 · 10^–5 g Fe, 2 · 10^–6–3,2 · 10^–5 g Pb et 3 · 10^–8–1 · 10^–5g Cu par g ZnS.

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Herrn Prof. Dr.A. A. Benedetti-Pichler zum 70. Geburtstag gewidmet. Vorgetragen am XI. Colloquium Spectroacopicum Internationale, Beograd, 1963.

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Wir danken auch an dieser Stelle HerrnP. Endröi für die Zubereitung der Standards mit Cu- und Fe-Zusatz und Herrn DirektorF. Kömüves für die Erlaubnis zur Publikation dieser Arbeit.     

Beiträge zur Neutronenaktivierungsanalyse von luminophorreinen Zinkverbindungen

Zusammenfassung Nach dem Vergleichsverfahren mit chemischer Aufarbeitung der Proben wurden in luminophorreinen Zinkverbindungen Co, Fe und Mn durch Neutronenaktivierungsanalyse bestimmt. Die Trennung wurde mittels Anionenaustauschchromatographie an Dowex 1 (Cl^–) bzw. Wof. SBW (Cl^–) durchgeführt. Die Empfindlichkeit des Verfahrens beträgt bei einem Neutronenfluß von 10¹³ n/sek. cm² 10^–8% Mn, 5 · 10^–7% Co und 5 · 10^–6% Fe. Die Standardabweichung der Einzelwerte liegt bei ±5%.

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Summary The comparison procedure with chemical processing of the samples was employed to determine Co, Fe and Mn in zinc compounds free of luminophors by means of neutron activation methods. The separation was made by anion exchange chromatography on Dowex 1 (Cl^–) or Wof. SBW (Cl^–). The sensitivity of the method, at a neutron flow of 10¹² n/sec.cm², is 10^–8% Mn, 5 · 10^–7% Co, and 5 · 10^–6% Fe. The standard deviation of the individual results is about ±5%.

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Résumé Suivant le procédé par comparaison avec traitement chimique des échantillons, on a dosé par analyse par activation neutronique le cobalt, le fer et le manganèse dans les composés du zinc non lumenophores. On effectue la séparation par chromatographie avec échange anionique sur Dowex 1 (Cl^–) ou Wof. SBW (Cl^–). La sensibilité du procédé s'élève dans le cas d'un flux de neutrons de 10¹² n/sec.cm², à 10^–8% Mn, 5 · 10^–6% Co et 5 · 10^–% Fe. La déviation standard pour une mesure isolée s'élève à ±5%.

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Die Verfasser danken Herrn Prof. Dr.C. F. Weiss für sein Interesse an dieser Arbeit.     

Preparation, characterization and crystal structure of Na4[Mn(NCS)6]·13H2O

Na₄[Mn(NCS)₆] · 13H₂O was prepared and characterized by chemical analysis, magnetic susceptibility, thermal dehydration reactions, and single crystal X-ray structure analysis. The crystals are triclinic with a=9.310(1)Å, b=9.367(1)Å, c=9.730(2)Å, = 89.89(1)°,=75.33(1)°, =70.72(1)°, space group P¯I.Z=1. The structure is built up from Na(H₂O)₅ S, Na(H₂O)₆, and Mn(NCS)₆, octahedra. All water molecules are coordinated to Na⁺ -ions in terminal as well as bridging fashion. They form O-H···O as well as O-H···S hydrogen bonds.Dedicated to Professor Dr. rer. nat. Dr. h.c. Hubertus Nickel on the occasion of his 65th birthday     

Low level measurements of thorium and neptunium in environmental samples using the (γ, f) reaction

A new highly sensitive track method for the determination of thorium (²³²Th) and neptunium (²³⁷Np) has been developed. The technique includes the radiochemical separation procedure of the isotopes followed by the irradiation of the resultant samples on the MT-25 microtron. The detection limit is équivalent up to 3·10^–13 g of²³²Th and 7·10^–14 of²³⁷Np. The method was used to determine²³²Th and²³⁷Np isotopes in water samples.     

Anreicherung und Bestimmung kleiner Mengen Kobalt neben Eisen in Nickel und Reinstnickelsalzen

Zusammenfassung Die Verwendung von Tri-n-butylphosphat zur Extraktion kleiner Eisen- und Kobaltgehalte aus neutraler thiocyanathaltiger wäßriger Phase führt zu beständigen, farbintensiven Lösungen, die eine gleichzeitige empfindliche photometrische Bestimmung dieser Elemente in Reinstnickel und Reinstnickelsalzen ermöglichen. Die Nachweisgrenzen des Verfahrens liegen für die von uns angewandten 10 g-Einwaagen bei 3 · 10^–6 % Fe bzw. 2 · 10^–5 % Co. Die relativen Standardabweichungen sind kleiner als 5%.

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Summary The use of tri-n-butyl phosphate for the extraction of small amounts of iron and cobalt from a neutral thiocyanate containing aqueous phase results in stable, colour-intensive solutions which permit a simultaneous sensitive photometric determination of these elements in high-purity nickel and nickel salts. The limits of detection of the procedure in 10 g samples are 3 · 10^–6 % Fe and 2 · 10^–5 % Co. The relative standard deviations are lower than 5%.

     

Radiochemical separation techniques for the determination of long-lived radionuclides in meteorites by means of accelerator-mass-spectrometry

Summary The record of the interaction of cosmic ray particles with meteoroids in space is preserved in these objects in radioactive and stable nuclides. In order to determine the low concentrations of long-lived radionuclides such as¹⁰Be (T _1/2=1.6×10⁶a),²⁶Al (T _1/2=7.2×10⁵a),³⁶Cl (T _1/2=3.0×10⁵a),⁴¹Ca (T _1/2=1.0×10⁵a),⁵³Mn (T _1/2=3.8×10⁶a) and⁵⁹Ni (T _1/2=7.5×10⁴a) in extraterrestrial material by means of accelerator-mass-spectrometry and neutron activation techniques, radiochemical separations with high decontamination factors of interfering isotopes have been developed. Detection limits are achieved down to 1×10^–14 for isotopic ratio measurements. For absolute analytical techniques they could be lowered to 10^–14g/g. The separation methods applied include ion exchange, solvent extraction as well as classical precipitation methods. The successful application of the procedure to problems in meteorite research is given by example.

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Radiochemische Trennverfahren für die Bestimmung langlebiger Radionuklide in Meteoriten mit Hilfe der Beschleuniger-Massenspektrometrie

     

Extraction-flame atomic absorption determination of microtraces of copper, zinc, nickel, cobalt, manganese and iron in some alkali salts

Summary The microtrace content of Cu, Zn, Ni, Co, Mn and Fe in NaClO₄, KCl, KOH and KAl(SO₄)₂ · 12 H₂O is determined by flame atomic absorption spectrometry after preceding preconcentration of the traces using the extraction system PMBP/MIBK. It is proved that the salt matrix does not affect the quantitative extraction of the traces. The method permits the determination of the traces in the concentration range of 10^–3–10^–6% with good precision (variation coefficient 2–8%) and accuracy.

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Extraktions-Flammenatomabsorptions-Bestimmung von Mikrospuren von Cu, Zn, Ni, Co, Mn und Fe in Alkali-Salzen

Zusammenfassung Der Mikrospurengehalt von Cu, Zn, Ni, Co, Mn und Fe in NaClO₄, KCl, KOH, und KAl(SO₄)₂ · 12H₂O wurde durch Flammenatomabsorption nach Extraktionsanreicherung mit einer 1-Phenyl-3-methyl-4-benzoylpyrazolon-5 (PMBP)-Lösung in MIBK bestimmt. Die Salz-Matrix weist keinen störenden Einflu\ auf die quantitative Extraktion der Elementspuren auf. Die Bestimmung der Spuren im Konzentrationsgebiet von 10^–3–10^–6% erfolgt mit guter PrÄzision (Variationskoeffizient 2–8%) und Richtigkeit.

     

Instrumental neutron activation analysis of geochemical and cosmochemical samples: A fast and reliable method for small sample analysis

We have developed a fast and reliable procedure to routinely measure the abundances of up to about 35 elements even in small (<1 mg) samples. Depending on the type of samples, they are either irradiated for about 8 hours at a flux of about 2·10¹²n·cm^–2·s^–1, or up to 100 hours at a flux of about 6·10¹³n·cm^–2·s^–1. As standards, high-purity synthetic multielement standards and well-characterized geological reference materials are used. Synthetic standards are used as primary standards because they have several advantages over secondary (geological) standards. Three to four counts are done one each sample, starting 1–3 days after the end of the irradiation. We use high-purity germanium (HpGe) detectors with high efficiencies and very good energy resolution (1.6–1.8 keV at 1332 keV). To allow high throughput rates we use fast preamplifiers and gated integrator spectroscopy amplifiers with fast fixed conversion time ADCs. The signals are fed into an acquisition interface module (AIM) and via Ethernet into a Micro VAX. To allow better peak deconvolution, 8k spectra are taken where possible. A specially designed annular NaI(TI) guard detector allows Compton suppression spectrometry. The system uses standard software and was tested with sets of geological standards and has given reliable results for a wide variety of samples, e.g., cosmic spherules in the 30–200 g weight range.     

Spectrophotometric determination of trace amounts of cadmium using Cd(II)-KI-Crystal violet system in the presence of triton X-100 and PVA

A new highly sensitive spectrophotometric method for determination traces of cadmium using Cd-(II)-KI-Crystal Violet system in the presence of Triton X-100-poly(vinyl) alcohol (PVA) mixture has been developed. The apparent molar absorptivity of the system is 1.77 × 10⁵ 1-mol^–1 cm^–1 and its Sandell's sensitivity is 6.35 × 10^–4 g·Cd·cm^2–. Beer's law is obeyed up to 0.32 g·Cd(II)·ml^–1. The method has been applied to determine Cd(II) in waste water, rice and pork meat samples with satisfactory results.     

Sulfurization of polymers. 5. Poly(6-methyl-5-sulfanylthieno[2,3-b]pyridine-4-thione), poly(thieno[2,3-b]azepine-4,5(6H)-dithione), and related structures from poly(2-methyl-5-vinylpyridine) and elemental sulfur

Poly(2-methyl-5-vinylpyridine) is sulfurized with elemental sulfur at 140—320 °C to release hydrogen sulfide and to give black lustrous powders (sulfur content up to 45%) possessing electric conductivity (6.4·10^–11—1.6·10^–7 S cm^–1), paramagnetism (spin concentration 6.2·10¹⁸—5.0·10¹⁹ sp g^–1, g = 2.0043—2.0046, H = 0.49—0.58 mT), and redox and complex-forming properties. Elemental analysis data, IR, ESR, and mass spectra, DSC and TGA data, electric conductivity, electrochemical activity and chemical properties (salt formation and complexation) of the materials synthesized correspond to cross-liked poly(6-methyl-5-sulfanylthieno[2,3-b]pyridine-4-thione), poly(thieno[2,3-b]azepine-4,5(6H)-dithione), and related structures.     

Triplet-triplet annihilation in dilute,solid solutions of aromatic polymers

Summary The triplet-triplet annihilation of mass fractionatedPVCA (M=3.6·10³–1.4·10⁶) in toluene glasses was studied by phosphorescence, for glasses ofPVCA andP2VN (order of M=10⁶) inMTHF the intensity of phosphorescence and delayed fluorescence were studied as a function of the excitation intensity. A survey of T-T annihilation in solid solutions of aromatic polymers is given and requirements for a theory explaining low dimensional energy transport and exciton-exciton annihilation are pointed out.Presented at the ACS-Symposium Polymer Photophysics: Fundamentals and Applications. ACS-Spring Meeting 1992, San Francisco, April 5–10, 1992     

Non-destructive gamma-spectrometry analysis of cosmogenic radionuclides in fragments of the Ko?ice meteorite

Results of analysis of cosmogenic radionuclides (^57,58,60Co, ⁵⁴Mn, ⁴⁶Sc, ²²Na, ⁴⁸V and ²⁶Al) in fragments of the Ko?ice meteorite are presented and discussed. Analyses were carried out using a low-level HPGe-spectrometer placed in a lead-iron-copper shield. Twelve meteorite fragments were available for the analysis with masses from 27 to 2,163?g. The lowest massic activities were observed for ⁴⁶Sc (down to 0.1?mBq/g), and the highest for ²²Na (up to 2?mBq/g). The measured radionuclide activities showed differences between fragments, as indicated mainly by the ⁶⁰Co data, which were caused by different positions of meteorite fragments from the center of the meteorite body.     

Auxiliary aromatic-acid effect on the structures of a series of Zn coordination polymers: Syntheses, crystal structures, and photoluminescence properties

Five novel Zn^II-(pyridyl)imidazole derivative coordination polymers, [Zn(L)₂] (1), [Zn₂(μ₃-OH)L(m-BDC)] (2), [Zn₂(μ₃-OH)L(p-BDC)]·H₂O (3), [Zn₂L(BTC)(H₂O)]·2.5H₂O (4) and [Zn_3.5(μ₃-OH)L₂(BTEC)(H₂O)]·H₂O (5) (L=4-((2-(pyridine-2-yl)-1H-imidazol-1-yl)methyl)benzoic acid, p-H₂BDC=1,4-benzenedicarboxylic acid, m-H₂BDC=1,3-benzenedicarboxylic acid, H₃BTC=1,3,5-benzenetricarboxylic acid, H₄BTEC=1,2,4,5-benzenetetracarboxylic acid), were successfully synthesized under hydrothermal conditions through varying auxiliary aromatic-acid ligands and structurally characterized by X-ray crystallography. Compound 1 exhibits a 1D chain linked via double L bridges. Compound 2 features a well-known pcu topology with bent dicarboxylate ligand (m-H₂BDC) as an auxiliary ligand, while 3 displays a bcu network with linear dicarboxylate ligand (p-H₂BDC) as an auxiliary ligand. The structure of compound 4 is a novel 3D (3,5)-connected network with (4·6²)(4·6⁴·8²·10·12²) topology. It is interesting that compound 5 shows an intricate (3,4,8)-connected framework with (4·6²)(4²·6³·8)(4²·6⁴)(4²·6¹⁸·7·8⁶·10) topology. In addition, their infrared spectra (IR), X-ray powder diffraction (XPRD) and photoluminescent properties were also investigated in detail.     

Determination of citrate in tablets and of oxytetracycline in serum using europium (III) luminescence

A direct method for the determination of citrate and oxytetracycline in samples containing complex matrices like tablets or serum has been developed using the luminescence of the ternary complex formed with Eu(III) ions. The triplet-state energy level of oxytetracycline (OxTc), the excitation maximum (412 nm) and the luminescence lifetime of Eu-OxTc (58 μs) were determined. A 17-fold luminescence enhancement at 615 nm occurs upon addition of citrate within a short 5-min incubation time at neutral pH. This is accompanied by a threefold increase of the luminescence decay time. The optimal conditions for determination of OxTc are equal concentrations of Eu (III) and citrate (C = 1 · 10^− 4 mol L^− 1) and pH 7.2. For determination of citrate, the optimal concentrations of Eu(III) and OxTc are 1 : 0.5 (C_Eu = 1 · 10^− 4 mol L^− 1, C_OxTc = 5 · 10^− 5 mol L^− 1) at pH 7.2. The linear range for determination of OxTc in serum is 0.25-250 μg mL^− 1, and for citrate in tablets from 0.5 to 10.0 μg mL^− 1 (2.3 · 10^− 6- 4 · 10^− 5 mol L^− 1). The detection limit was 0.1 μg mL^− 1 for OxTc and 0.2 μg mL^− 1 (1 · 10^-6 mol L^− 1) for citrate, respectively. A comparison of the new method with other methods for determination of citrate is given.     

Determination of impurities in zircaloy clad by means of neutron activation analysis

A method is described for determining impurities in Zr-2 and Zr-4 clads by means of instrumental neutron activation analysis followed by high resolution gamma-ray spectrometry. The samples were irradiated in IRT-5000 using vertical channels and a pneumatic system with neutron fluxes of about 3·10¹³ and 4.8·10¹¹ n·cm^–2·s^–1, respectively, and counted using Ge(Li) detectors coupled to an on-line computer. The following impurties have been determined Al, Cr, Mn, Fe, Co, Ni, As, Sn, Sb, Hf and W.     

Spectrophotometric determination of 1-naphthylamine in urine with pentacyanonitrosylmanganate (II)

A new Spectrophotometric method is proposed for the determination of 1-naphthylamine (R), based on its reaction with Mn(CN)₅NO^2– to form Mn(CN)₅NH₂R^3– and measurement of the absorbance at 472 nm. In aqueous medium the molar absorptivity of the manganese complex is maximum ( = 8.0 × 10³1 · mole^–1 ·cm^–1) in the pH range 5.0–10.0, the colour develops more rapidly at pH 10.0. The absorptivity is increased by a factor of 3.5 if the complex is extracted as an ion-associate into chloroform. The extraction efficiency is 99.2% for a single-step extraction, and a concentration factor of 5 can also be achieved. Linearity of response extends over the range 0.04–1.4 gmg/ml 1-naphthylamine, the coefficient of variation being 1.4% at the 0.29 g/ml level (n = 6). The detection and determination limits are 0.005 and 0.018 g/ml, respectively. The method is selective enough to allow the determination of 1-naphthylamine in the presence of considerable amounts of other amines, such as aminophenols and phenylenediamines. Results obtained in the determination of 1-naphthylamine in human urine were very satisfactory.     

Extractive spectrophotometric determination of palladium from acidic high activity nuclear waste

A simple and rapid method for spectrophotometric determination of palladium from highly acidic and highly radioactive nuclear waste using -benzoin oxime (ABO) as extractant and isobutyl methyl ketone (hexone) as diluent has been developed. The method can be employed over a wide range of nitric acid concentrations and for palladium concentrations in the range of 1·10^–5M to 4·10^–4M in the organic phase. The molar absorptivity was found to be 4·10³l·mol^–1·cm^–1. Influence of various heavy metal ions, fission products and corrosion products was studied. The method was found to give a precision and accuracy better than 4% at 100 g of palladium.     

Crystal structure of a cyanide-bridged heptanuclear manganese(III)–chromium(III) complex with a ground state S = 21/2

K₃[Cr(CN)₆] reacts with the mononuclear Mn^III complex Mn(salen)ClO₄ · 2H₂O [salen: N,N-ethylenebis(salicylideneiminato)dianion] to give a bimetallic heptanuclear complex cation salt [Cr{(CN)Mn(salen · H₂O)}₆][Cr(CN)₆]6H₂O. In the complex anion, [Cr{(CN)Mn(salen · H₂O)}₆]³⁺, six Mn^III ions coordinate to a Cr^III center via cyano bridges, forming a spherical species with 3 symmetry. A study of magnetic properties shows the presence of antiferromagnetic interaction through the cyanide bridge between Cr^III (S = 3/2) and Mn^III (S = 4/2) and results in a ground state S = 21/2.