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Based on a Preloaded Digital Filter operating on a 20% n-type HpGe detector with transistor reset preamplifier, and on a software implementation of a loss-free counting MCA, storing immediately into the multi-megabyte main memory of a low-cost 486-type PC, the new system enables the collection of up to 120 pairs of simultaneously recorded loss-corrected and non-corrected spectra of 16 k channels each, in a true sequence without time gaps in between, at a throughput rate of up to 140 kc/s. Intended for activation analysis of short-lived isomeric transitions, the system for the first time makes possible peak to background optimizations and even separations of lines with different half-lives without an a priori knowledge of sample composition by summing up appropriate numbers of spectra over appropriate intervals of time. The speed of this programmable system also made possible the direct comparison of two methods of real-time correction of counting loss, by simultaneous recording of LFC-corrected, ZDTtm-corrected and non-corrected spectra together with their corresponding weighting factor distributions.

The usual mass of samples for activation analysis is in the range of several milligrams to several hundred milligrams. An improvement of the detection limit by three orders of magnitude is attainable by use of a larger sample size. Limitations of the method due to thermal effects, neutron self-shielding and gamma-ray attenuation during activation and measuring of large organic samples are discussed.

Fields in which progress has been achieved at the Atomic Institute Vienna are discussed briefly. The use of short and medium lived nuclides for activation analysis (AA). Construction of out-core parts of a fast transfer system. Combined sample catcher sample-changer for AA allowing cyclic and pseudocyclic AA. A system for discontinuous or continuous irradiation of liquid samples. Counting with an anticompton shield and quantitative correction of random coincidences. Screening analyses with the fast irradiation and measurement system. Improved peak-evaluation of gamma-spectra. Epithermal AA by a neutron converter. Following short-lived nuclide measurement, automatic sample transfer into a well-type detector enabling sensitive counting of nuclides with short half-lives. Use of large samples to increase the detection limits of ng to pg at activation with moderate neutron flux. Flux determination by liquid scintillation counting.

The irradiation of large samples of biological material in a high neutron flux enables the extention of trace element analysis into the ng to pg range, but raises several problems as gamma heating and radiolysis degrade the samples. Gamma heating increases the pressure to a point where either a very large irradiation container is necessary or a container which can endure the high pressure. Several methods to overcome these problems have been published. The irradiation of open samples was performed as an alternative to these methods. Temperature effects on biological material during irradiation in a high and in a low neutron flux were compared. As an example, wheat was irradiated in open containers allowing simultaneous temperature measurement in the sample during irradiation.

The palladium-catalysed addition of allylic chlorides to carbonucleophiles leads to the formation of new terpene derivatives. A facile and economical route of phytone is described.

Abstract: Neutron activation analysis (NAA) at various irradiation and measurement systems of the Institute's TRIGA mark II reactor provides a choice of sample oriented analyzing systems. This is demonstrated on the analysis of waste products, on an analysis of the phase content of a high-Tc superconductor and on a fluorine analysis in a standard reference material.

Abstract: Short time activation analysis was applied to the analysis of reactor emergency poisoning solutions, to the analysis of doping elements in small organic semiconductor specimens, for the analysis of high temperature superconductors, and the determination of fluorine in various materials including biopsy samples. All the halogens in waste water were analyzed by a single 20s activation followed by two successive counting periods of 20 and 200s.

Abstract: A new counting geometry with a simple sample changer was constructed to enable cyclic and pseudocyclic short-time activation analysis. With the new system it is possible to cycle a sample, or successively an indefinite number of samples up to 20 times. The sample changer acts at the same time as sample catcher for two n-type HPGe detectors and can release the sample into a well-type HPGe detector. The new system enables the simultaneous counting of the irradiated samples by means of two endcap HPGe detectors, and subsequent counting by means of the well HPGe detector or both detector types. A well detector ensures a high counting efficiency which improves the sensitivity of a large number of short lived nuclides. Some standard reference materials (i.e., BCR-176, NIST SRM 1633b, IAEA-336, 335b, 335c) were prepared and analysed in replicates. The results indicate that up to 46 nuclides can be determined in BCR-176 if the samples are irradiated with and without the6LiD converter. An automatic evaluation programme was developed that determines the FWHM calibration parameters for each spectrum for accurate peak-area estimation at high count rates.

The detection limits in neutron activation analysis are up to the standards of extraterrestrical matter analysis. Instrumental analysis is possible only after a group separation of the rare earth elements. The measurements requires a 26 day decay period. If results are desired within a shorter time interval the individual rare earth elements have to be separated. Gas chromatography and electrophoresis were applied in this work. Gas chromatography of metal chelates using radioactive reagents with high specific activity significantly improves the detection limits. The gas-chromatographic separations, however, should be only regarded as model experiments. The experimental results were obtained much faster (within 12 h) by applying high voltage electrophoresis of rare earth elements. Because of the excellent separation, the rare earth elements can be determined by automatic ß-liquid scintillation spectrometry with high counting yields.

Abstract: Sediment samples of the High Dam lake were investigated for their137Cs,226Ra,228Th, and40K content, using low-level gamma-spectroscopy. The results show that at the begining of the lake (500 km from the High Dam), where sediments consist mostly of sand, the level of137Cs is very low (0.1 Bq kg–1). The maximum value (22.3 Bq kg–1) was found 40 km from the wall of the High Dam, where the composition of the sediments is nearly 50% clays. The distribution of the natural nuclides226Ra,228Th, and40K shows a different trend.

Abstract: Different reference materials of environmental and geological origin, such as NBS 1633a (Coal Fly Ash, CFA), NBS 1645 (River Sediment, RS), GXR-2, and IAEA Soil-5, were investigated by short time activation analysis. The samples were analyzed in 5 replicates each between 100 to 150 mg, at neutron flux of 1.3 E 12 cm–2 s–1, using a high rate — high resolution gamma spectroscopy with a Loss Free Counting (LFC) System to correct the dead time and pile up to 500,000 cps. The results of the measurements indicate that the precision in determination of28Al,46mSc, and52V is between 1 to 6%. Different evaluation programs (i.e. ALCHEM, AKTAN, and ND-PEAK) were used to calculate the peak areas. The results indicate that, at lower counts, the statistical error of peak area calculation becomes more significant. Finally, Mössbauer spectroscopy was used to investigate the main Fe compounds present in some reference materials.

Abstract: Fluorine has been analyzed in the ldquoFast Irradiation and Measurement Systemrdquo FIMS in the TRIGA Mark II reactor. The samples with weight ranging from 100 to 500 mg were irradiated and measured in 11 or 22 s periods. The applicability of the proposed method for widely different sample types is discussed. Results are divided into three main groups with regard to the sample type. The first group comprehends low level alumina, plants and other biological materials of organic origin, the second covers the medium level alumina sediments, sewage and soils, and the third the rocks with high alumina contents, and minerals.

Abstract: k0- and Q0-factors of 18 short-lived nuclides used in reactor neutron activation analysis were determined using the Fast Irradiation and Measurement System (FIMS) of the TRIGA MARK II reactor at the Atominstitut der Österreichischen Universitäten. The Q0-factors were either critically selected from literature, or experimentally determined according to theldquoCd-ratiordquo method, while the k0-factors were additionally determined by theldquoBare monitorrdquo method. A comparison is made with the values calculated by introduction of literature data for the input parameters. Moreover, a user oriented tabulation is presented of k0-, Q0-factors and related nuclear data. All results were critically tested with respect to their accuracy and precision.

Abstract: As a basic step to quality assurance of INAA via shortlived isomeric transitions replicate analyses of NaCl are performed on an INAA facility specifically designed for this purpose and from the series of net peak areas of Na-24m (20 ms) and Cl-38m (715 ms) it can be shown that the system is quantitative and that its precision is determined by counting statistics. Future improvements of the method may be expected from gamma spectrometry systems with higher throughput and better resolution than that of the now used gated integrator. A resolution comparison between a gated integrator and the recently developed Preloaded Filter is given on the basis of the detector applied in this investigation and substantial improvements are examplified.

Abstract: Short-time activation analysis is applied to the analysis of bastnaesite, a rare-earth fluorocarbonate and to uranium analyses of the IAEA ore standards S-7 and S-8, using the 2 and 6s groups of delayed neutrons. It is further applied after enrichment procedures for the determination of B in water by the 20 ms B12 activity of Au in sediments after enrichment on carbon by the 7.8 s197mAu, and of a magnetically-separated heavy fraction of bituminous coal NBS-SRM 2683. Analysis after sensitivity enhancement by repeated activation of subsamples is demonstrated by the determination of Na in K-feldspar by the 20 ms24mNa activity. Analysis after pulse activation is demonstrated on NBS-SRM 1648 Urban Particulate.

Abstract: Major, minor, trace and ultratrace concentrations of Ag, Al, As, Au, Ba, Be, Br, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Dy, Eu, Fe, Ga, Hf, K, La, Li, Lu, Mg, Mn, Na, Nb, Ni, P, Pb, Sb, Sc, Se, Sm, Sn, Sr, Ta, Th, Ti, U, V, W and Zn in crude juice, principal juice, sirup juice (produced during the successive stages of sugar industry), sugar cane plant, molasses, deposits (produced as a result of the addition of Ca(OH)2 and superphosphate and passage of SO2 through juice), A-and B-sugar and soil samples have been determined by destructive and nondestructive instrumental neutron activation (INAA), atomic absorption spectrophotometric (AAS) and inductively coupled plasma-atomic emission spectrometric (ICP-AES) analyses. The results obtained by the methods applied are in excellent agreement. Concentrations of the elements are different. Variations in element concentrations in cance plants and in crude juice may be attributed to composition changes or different botanical structures; in mixed juice, sirup, molasse and deposits they may be due to chemical treatments or corrosion effects on containers, whereas in soil samples to geochemical and biogeochemical fractionation as a result of adsorption and uptake of trace elements by plants from surrounding soil solutions.

Abstract: Lake Nasser, one of the largest man made lakes in the world, is the reservoir created by the High Dam in the southermost part of Egypt and extends beyond Daal Cataract in the Sudan. The reservoir is about 480 kms long, of which, 300 kms are in Egypt (Lake Nasser) and 180 kms in the Sudan (Lake Nubia) and extends approximately within the latitudes of 21 No in the Sudan and 24 No in Egypt. In the west is the Great Western Desert and in the east the Eastern Desert of Egypt which extends up to the Red Sea. The deepest part is found near the High Dam (Lake Nasser) which reaches approximately about 86 metres. The depth decreases to the south and reaches approximately about 15 meters at Akasha in the Sudan. The Lake is much more wider in the egyptian part. The attached map shows the geographical locations of the lake from which the samples were collected. This work deals with the determination of 38 trace elements in water by neutron activation analysis (NAA). Also some parameters such as pH, (electric conductance), CO2−, HCO 3− , CO2, SO 42− , residue (after evaporation), dissolved oxygen, NO 2− and temperature were determined in the field. The temperature ranged from 20.7–29.7°C, while the pH values from 7.45 to 9 (for the bottom and surface waters). The dissolved oxygen was determined and found to be 0.8–9.4 mg/l for bottom and surface waters, respectively.

Abstract: A study was undertaken to determine element concentrations in Aswan High Dam Lake sediments. Sediment samples were collected from 40 to 500 km upstream of the dam to follow the sedimentation process and the distribution of Th, U and the trace elements in the lake. INAA was applied for the determination of Sm, Ce, Lu, Th, Cr, Yb, Au, Hf, Ba, Nd, Cs, Tb, Sc, Rb, Fe, Zn, Co, Eu, and Sb, while Laser Fluorimetry was applied for U determination. The accuracy and the reproducibility of the techniques were tested with IAEA standard materials (SL, Soil-7). The U values ranged from 4 ppm to 18 ppm, Th values were between 2 and 10 ppm, and showed a very good correlation with the rare earth elements and Fe. The distribution of most of the elements in the lake follows the same trend as the distribution of the clays in the sediments. Ba showed a negative correlation with most of the elements under investigation.

Abstract: An intercomparison of data obtained for a moss reference material (Hylocomium splendens) used as biomonitor of atmospheric deposition by different multi-element techniques is presented. In total 43 elements (Na, Mg, Al, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Zr, Ag, Sn, Sb, I, Cs, Ba, La, Ce, Nd, Sm, Eu, Gd, Tb, Tm, Yb, Lu, Hf, Ta, W, Au, Th, U) were determined using inductively coupled plasma-mass spectrometry (ICP-MS), conventional instrumental neutron activation analysis (INAA), epithermal neutron activation analysis (ENAA) and as well as shorttime neutron activation analysis without and with a6LiD-converter. Advantages and drawbacks of each method are discussed. The introduction of moss reference materials for atmospheric multi-element deposition studies involving nuclear analytical techniques is strongly recommended.

Abstract: Instrumental neutron activation analysis was used for the determination of Al, Br, Ca, Ce, Cl, Co, Cr, Cs, Eu, Fe, K, La, Mg, Mn, Na, Rb, Sb, Sc, Se, Ti, Th, V and Zn, ICP-AES for the determination Al, Ag, Ba, Be, Ca, Co, Cr, Cu, Fe, Ga, K, Li, Mg, Mn, Na, Ni, P, Sc, Sr, Ti, V and Zn and flameless AAS for the determination of Cd, Hg and Pb in egg plant, potatoes, green pepper (Leguminosae), vegetable marrow (Cucurbitaceae), pears, apple (Rosaceae), castor oil plant (Euphorbiaceae), lettuce (compositae), dill, parsley, coriander (Umbelliferae), and in some soil samples collected from Aswan province.

Abstract: Multielemental instrumental neutron activation (INAA), inductively coupled plasmaatomic emission spectrometric (ICP-AES) and atomic absorption spectrophotometric (AAS) analyses are utilized for the determination of Ag, Al, As, Au, Ba, Be, Br, Ca, Cd, Ce, Cl, Co, Cr, Cu, Eu, Fe, Ga, Hf, K, La, Li, Lu, Mg, Mn, Na, Nb, Ni, P. Pb, Sb, Sc, Se, Sm, Sn, Sr, Ta, Th, Ti, U, V, W and Zn in sugar cane plant, raw juice, juice in different stages, syrup, deposits, molasses, A, B and C sugar, refinery 1 and 2 sugar, and in soil samples picked up from the immediate vicinity of the cane plant roots at surface, 30 and 60 cm depth.

Abstract: A high-resolution high-rate ψ-spectroscopy system is essential or, respectively, useful in three groups of applications: (1) measurement of nuclides with half-lives of less than one second; (2) Measurement of nuclides with half-lives in the second range at high sample activity; (3) Measurement in the same counting geometry of sample series of highly different sample activities. Examples are given for these applications.

Abstract: Boron and lithium content in various glass fiber-optics, enamel, and lake sediments were determined by measurement of the Cerenkov-radiation of12b and8Li using the fast rabbit-system of the Atominstitute. The decay-curves were also measured using a dead time correction unit (LFC) and evaluated with respect to interferences of other short-lived nuclides. Simultaneously, γ-spectra of short-lived nuclides were measured with the LFC-system. Main interferences in Cerenkov-counting were observed from28Al and16N. High count-rates were measured correctly with the LFC-system. The halflives of8Li and12B were determined as well as their detection limits in glass and lake-sediments.

Abstract: A rapid vertical transportation system for irradiation with thermal and fast neutrons is devised and partly constructed for inserting samples into the central thimble of our TRIGA MARK II reactor. Fast neutrons will be produced by a6LiD-converter, so that the energy distribution of neutrons is hardened by absorption of thermal and by the production of 14 MeV neutrons. In pulse irradiation, the 14 MeV-neutron flux is expected to be in the order of 1012/s. The transportation time is to be below 30ms to enable determination of short-lived nuclides down to 15ms. Helium will be used as propelling gas.

Abstract: On irradiation with neutrons, some of the interesting trace elements in coal, coal ash and fly ash produce short-lived nuclides which may be determined—together with some of the matrix elements—by activation analysis. This enables the characterization of samples. To find out the distribution of elements in the gaseous or aerosol exhaust of fossil-fired power plants, we simulated the combustion in a quartz apparatus containing a cold trap, using the combustion temperature (780 °C) employed for the standard ash determination. High Se values were found in the cold trap deposits from black coal from Poland. Halogens were also found in the deposits.

Abstract: By means of electrophoretic focussing relatively large amounts can be separated into groups. It is shown that an even better separation can be achieved in a two-dimensional method. The first step of a normal zone electrophoresis is followed by electrophoretic focussing. A sample containing about 0.3 mg metal-ions was separated within 20 minutes. A further advantage over other two-dimensional methods is that the ions are concentrated into small zones by the second step.

Abstract: Analyzing environmental samples it is often necessary to determine traces in a matrix or to separate elements easily activated. In this case the detection limit depends on the amount of sample which can be separated. Frequently group separations are sufficient. In this paper we describe the relationship between amount, focussing area and concentration of the electrolytes in electrophoretic focussing. The load capacity and the possibility of group separations are evaluated. It is shown that within 4–5 min up to mg amounts can be separated into at least five groups on a 2 cm broad strip and that the ions are concentrated into small zones with a concentration of up to 1 mg·cm−2.

Zusammenfassung Im Hinblick auf größere Auftragungsmengen wurde eine Elektrophorese anorganischer Ionen auf Polyacrylamidgel sowie auf Kieselgel beschrieben. Auf PAA-Gel wurde auch mit gewöhnlicher Elektrophorese gearbeitet, auf beiden Trägern konnten mit der Methode der elektrophoretischen Ionenfokussierung einfache Trennungen von Systemen mit teils stark unterschiedlichen Mengenverhältnissen durchgeführt werden.

INAA, AAS and ICP-AES techniques are applied to the determination of trace amounts of Ag, Al, As, Au, Ba, Br, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Dy, Eu, Fe, Ga, Hf, K, La, Li, Lu, Mg, Mn, Na, Nb, Ni, Pb, Sb, Sc, Se, Sm, Sn, Sr, Ta, Th, Ti, U, V, W and Zn in the stalks of sugar cane plant after extracting juice, raw juice principal (mixed) juice, juice withdrawn from the successive stages of sugar industry, sirup, deposits from evaporators, molasse, A-? and B-sugar and in the soil samples (collected from the field supplying the factories by cane plants) taken from the immediate vicinity of the plant roots at surface, 30 and 60cm depth. The results obtained are in a good agreement of the safety baselines of using juice as beverage, molasse derivatives (honey, sweets,…) as diet for common people in the developed countries and in industry (methanol, ethanol, acetone & acetic acid,…) and sugar sweeting for many purposes (in beverages, desserts,…). Differences of trace elements concentrations in soil samples may be reasoned to geochemical and biogeochemical fractionation while those in juice may be due to the changes in the environmental conditions, chemical composition and botanic structures. Variations in trace element contents in the products formed during the successive stages of sugar industry may be a result of evaporation, filtration processes, chemical treatments or corrosion of vessels, containers or engines. Trace elements are very important where they are responsible for enzymatic and biochemical reactions, matabolism, health and diseases.

The Cretaceous/Tertiary boundary has been identified in the Gosau beds (Elendgraben) near Salzburg, Austria. The undisturbed 2-mm thick boundary clay in the palaeomagnetic G−zone differs from the surrounding sediments in having significant colour, no biogenic calcite and different contents of rare-earth and siderophile elements, carbon and magnetic minerals. The clay also contains shocked quartz and plagioclase particles, and indicates a dramatic change in sedimentation caused by a short-lived event.

The application of short-lived nuclides, especially in connection with the6LiD-converter, in biological and environmental samples is demonstrated on I and Br determination in human urine, on I in pet food, and on the analysis of all the halogens in volcanic gases in a single activation. Trace element determination in lichens indicates polluted and unpolluted areas. The use of the 74-s38mCl enables the rapid screening of great number of samples.

Durch Untersuchung der „dichroitischen Verhältnisse” an zwei Modifikationen des Hexahydrophenthiazins konnte die Konformation der Verbindung I (Schmp. 100–101°) als ee-Form erkannt werden. Der Verbindung II (Schmp. 107–110°) kommt die ae- oder die ea-Form zu.

Es wird die Arbveitstechnik für die elektrophorese anorganischer aktiver Katinen auf einem Acetylcelluloseträgrmaterial (Cellogel) beschrieben. Die Vorteile dieser Technik werden an Hand von zahlreichen Beispielen dargeleft. Besonders erwähnt werden Trennungen von Seltenen Erden, Erdalkalien und Spaltprodukten.

It is shown that the electrophoresis of rare earths on Cellogel in a-hydroxy-isobutyric acid is suitable for the separation of minute amounts of carrier-free activities from neutron-activated earths. This is demonstrated by a separation of promethium from neutron-activated neodymium, in which the purity of the separated activities is determined by their ?-spectra.

In dieser Arbeit wird die Herstellung von Chelataustauschern auf Oxinbasis durch Vernetzung von Oxinaten mit Furfurol und Resorcin beschrieben. Mit Hilfe der Verteilungskurven wird gezeigt, daß die Selektivität der Chelataustauscher durch Zusatz bestimmter Ionen, wie Ba und Al, bei der Herstellung der Harze beeinflußt werden kann. The preparation of chelase resins on the basis of metal oxinates cross-linked with furfural and resorcinol is given in this paper. By means of the distribution coefficients it is shown, that the selectivity of chelate resins depends on the addition of certain ions, e.g. Ba and Al during the preparation.

Es wurde festgestellt, daß bei der mehrfach in der Literatur beschriebenen Umsetzung von o-Aminothiophenol mit Cyclohexenoxyd in alkalischer Lösung nicht Hexahydrophenthiazin entsteht, sondern 2-Hydroxy-cyclohexyl-2-aminophenyl-sulfid. Wirkliches Hexahydrophenthiazin ist bisher unbekannt und aus der Literatur zu streichen. Die Untersuchungen und Richtigstellungen wurden auf eine Reihe von Derivaten des “Hexahydrophenthiazins” ausgedehnt.

Bei derSzilard—Chalmers-Reaktion von Chromaten wird für Ammoniumverbindungen eine anomal kleine Retention gefunden.Harbottle nimmt als Erklärung dafür eine Reduktion der Rückstoßfragmente durch das Ammonuimion an. Um die Richtigkeit dieser Hypothese zu prüfen, wurde nach weiteren Chromaten mit anomal kleiner Retention gesucht. Die Tatsache, Daß Guanidinchromat von allen bisher untersuchten Chromaten die kleinste Retention ergab, spricht ebenso für dieHarbottlesche Hypothese wie unsere Versuche, bei denen eine reaktive Matrix simuliert wurde, und zwar durch Neutronenbestrahlung von Gemischen von K2CrO4 mit Saccharose, wobei wir die Retention von Null ermittelten. Dies bedeutet, daß wir ein System erhalten hatten, bei dem der Neutroneneinfang mit 100% chemischer Zustandsänderung verbunden war.

Durch Messung der Verteilungskoeffizienten wird der Nachweis erbracht, daß Chelataustauscher durch Zusatz von Metalloxinaten, z. B. von Al- und Ba-Oxinat, während der Kondensation der Harze selektiver gemacht werden können. In dieser Arbeit werden die pH-lg ?ex-kurven verschiedener Oxinatharze diskutiert. Die Form der Kurven wird aus dem Zusammenwirken von Komplexbildung, Donnan-Verteilung und Austauschvorgängen mit Carboxylgruppen abgeleitet. Die Steigungen der pH-lg ?ex-kurven werden als Maß für die mittlere Ligandenzahl verwendet. Die Selektivität der Austauscher wird durch die pH100-Werte charakterisiert. Damit wird der Nachweis erbracht, daß die sterische Anordnung des Oxins im Harz für die Selektivität mitverantwortlich ist.

Zusammenfassung Eine Arbeitsvorschrift zur Bestimmung Seltener Erden in Chondriten durch Neutronen-Aktivierungsanalyse und nachfolgende Auftrennung der Seltenen Erden durch Hochspannungselektrophorese wird beschrieben. Die Verteilung der SE-Elemente La, Ce, Pr, Sm, Eu, Dy, Ho, Er, Yb und Lu wurde in acht Meteoriten bestimmt. Die Ergebnisse werden mit früher erhaltenen Daten verglichen.

Zusammenfassung Die Anwendung der Hochspannungselektrophorese zur Trennung von Gemischen Seltener Erden in einem Medium vona-Hydroxyisobuttersäure wurde untersucht. Experimente auf Papier und Acetylzellulosefolien werden beschrieben. Nachdem die Trennung ausgewählter Lanthaniden gelungen war, konnte schließlich auch die Auftrennung aller Seltenen Erden erreicht werden. Die Trennzeiten betrugen 15 bis 20 Minuten. Die Anwendungsmöglichkeit für Transurane wird kurz diskutiert.

Zusammenfassung In Fortsetzung früherer Arbeiten wurde die elektrophoretische Trennung von Gemischen Seltener Erden ina-Hydroxyisobuttersäure auf Cellogelstreifen mit radioaktiven Nukliden untersucht. Die Reinheit und die Sequenz der Erden auf den Elektropherogrammen wurde durch das Abklingen der einzelnen Aktivitäten und durch Aufnahme von?- Spektren gesichert. Aktivierungsanalytische Nachweismöglichkeiten unmittelbar auf den Elektropherogrammen werden demonstriert. Mischungen aller Lanthanoide können einwandfrei aufgetrennt werden.

Das chromatographische Verhalten einiger Actinoide und Lanthanoide auf Dünnschichten aus Cellulose, Anionenaustauschern und Kationenaustauschern wird untersucht. Als Laufmittel wird eine Mischung von Isopropylalkohol, Wasser und HCl angewendet und die Abhängigkeit derRf-Werte von der Zusammensetzung dieser flüssigen Phase bestimmt. Aus den Ergebnissen kann geschlossen werden, daß die eingesetzten Ionen bei den gewählten Versuchsbedingungen in keinem Fall als anionische Komplexe vorliegen. Auf eine Trennmöglichkeit der eingesetzten Ionen wird hingewiesen.

2,5-Dimethyl-2,5-dioxy-1,4-dithian wurde unter Ringöffnung und Bildung von monomerem Acetonylmercaptan mittels D2O deuteriert. In der wieder cyclisierten Verbindung ist der Wasserstoff der OH-Gruppen durch Deuterium ersetzt. Daraus ergibt sich, daß die Bildung des Ringsystems über eine polarisierte CO-Gruppe des monomeren Acetonylmercaptans vor sich geht. Das UR-Spektrum der deuterierten Verbindung zeigt eine Verschiebung der OD-Bande nach längeren Wellen. Wir sehen dies als weiteren Beweis für die Existenz von H- bzw. D-Brücken zwischen O und S an.

Für beide in der Literatur unter der Bezeichnung Acetonyl-mercaptan beschriebenen Verbindungen wurde durch UR-Spektroskopie die Struktur eines 2,5-Dimethyl-2,5-dioxy-1,4-dithians bewiesen. Die beiden Formen wurden zu den konstanten Schmp. 117 bis 118° für die vonHromatka undEngel1 beschriebene Verbindung und 136 bis 138° für die vonGroth2 beschriebene Verbindung gereinigt. Aus Röntgen-untersuchungen geht hervor, daß in beiden Verbindungen der 1,4-Dithianring in Sesselform mit trans-ständigen OH-Gruppen vorliegt. Die Isomerie beruht auf Verschiedenheiten der Konstellation. In der bei 117 bis 118° schmelzenden, monoklinen Verbindung sind beide OH-Gruppen axial, in der bei 136 bis 138° schmelzenden, triklinen Verbindung äquatorial angeordnet. Der Zusammenhalt der Moleküle im Kristallgitter erfolgt zwischen O und S verschiedener Moleküle durch Wasserstoffbrücken. Es wird damit das erste Beispiel für Wasserstoffbrücken zwischen S und O in organischen Verbindungen aufgezeigt.

Abstract: The electrophoretic separation of radioactive rare earths on Cellogel in α-hydroxyisobutyric acid is described. Minute amounts of radioactive daughter nuclides are separated from the neutron-irradiated rare earth target materials, the ratio of the substances being 105∶1 to 107∶1. The suggested method is simple, rapid and suitable for analytical purposes.

In der vorliegenden Arbeit wird ein Chelationenaustauscher mit 8-Hydroxychinolin als chelatbildender Gruppe beschrieben. Es war möglich, das Austauscherharz durch direkte Kondensation von Metallchelaten mit Resorcin und Furfurol zu gewinnen, wodurch die Lagerung der planaren 8-Hydroxychinolingruppen von der Art der Herstellung abhängig wurde. Auf diese Weise wurden Al-Oxinat (oktaedrisch), Ba-Oxinat (planar-quadratisch) und Na-Oxinat mit der Matrix vernetzt. Die gewonnenen Harze zeigten gute Stabilität gegen Säuren und Laugen und konnten für Trennungen an der Säule verwendet werden. So konnte eine Trennung von Ru, Zr, U und Oe am Ba-Harz ausgeführt werden, wobei Ru-106, Zr-95 und Ce-144 trägerfrei vorlagen. Außerdem wird eine weitgehende Trennung des U von seinen Spaltungsprodukten und Np beschrieben. Auch die Strahlungsbeständigkeit der Austauscherharze läßt eine Verwendung für die Aufarbeitung stark radioaktiver Lösungen möglich erscheinen. A chelate ion exchanger is described with 8-hydroxyquinoline as chelate forming group. It was possible to obtain the exchange resin by direct condensation of metal chelates with resorcinol and furfuraldehyde, whereby the arrangement of the planar 8-hydroxyquinoline groups became dependent on the method of preparation. Al-oxinate (octahedral), Ba-oxinate (planarquadratic) and Na-oxinate were cross linked with the matrix in this way. The resins obtained showed good stability toward acids and alkaline solutions and could be used for separations on the column. A separation of Eu, Zr, U and Ce was accomplished, in which carrier-free Ru-106, Zr-95 and Ce-144 were present. Furthermore a far-reaching separation of uranium from its fission products and neptunium is described. In addition, the stability against radiation of the exchange resins makes it likely that they may be employed for the working up of solutions that are highly radioactive. On décrit, dans l'étude qui est présentée, un échangeur d'ions chélates avec l'hydroxy-8 quinoléine à l'état de groupes formant des chélates. Il a été possible d'obtenir la résine échangeuse par condensation directe de chélates métalliques avec la résorcine et le furfural, ce qui a entraîné un rapport entre la position des groupes hydroxy-8 quinoléiques planaires et le mode de préparation. De cette manière, l'oxinate d'aluminium (octaédrique), l'oxinate de baryum (planaire-quadratique) et l'oxinate de sodium se sont trouvés pris dans la matrice. On a pu ainsi réalisé une séparation du Ru, Zr, U et Ce sur résine au baryum et dans ces conditions Ru-106, Zr-95 et Ce-144 se présentaient sans support. On décrit en outre une séparation plus avancée de l'uranium d'avec ses produits de dédoublement et d'avec le Np. La stabilité contre l'irradiation de la résine échangeuse aussi, rend possible une. application pour le traitement de solutions fortement radioactives.