Separation of strontium-90 and yttrium-90 in the presence of thorium-234 by dynamic ion chromatography

A relatively rapid (<20 min) technique is described for the analysis of ⁹⁰Sr and ⁹⁰Y in the presence of ²³⁴Th. The method joins ion-chromatography and on-line scintillation detection. Experiments were performed to characterize separation of the three radionuclides in an Ion Pac CS5 ion-exchange column under the influence of the following eluents: oxalic acid, diglycolic acid (DGA), -hydroxy isobuteric acid (HIBA), and a mixture of hydrochloric acid and ammonium sulfate. Ammonium sulfate was the most effective of the eluents tested, yielding a resolution of 2.04 for strontium/yttrium and 1.03 for strontium/thorium. Within the limits of experimental uncertainty, the recoveries were quantitative for ⁹⁰Sr and ⁹⁰Y in the presence of 17 to 262 Bq·ml of ²³⁴Th.The authors thank Professor Dr R. A. Fjeld, Department of Environmental and Engineering Science, Clemson University, USA, for his helpful support and discussion.     

Estimation of 90Sr in reprocessed uranium oxide samples

Summary A method has been developed for the estimation of ⁹⁰Sr in reprocessed uranium oxide samples obtained from the Purex processing of natural uranium spent fuel discharged from the research reactor. The method employs a combination of precipitation and solvent extraction procedure to eliminate other beta-impurities prior to resorting to the estimation of ⁹⁰Sr by beta-counting. ¹⁰⁶Ru was eliminated by volatalizing with perchloric acid, uranium was removed by carrier precipitation with strontium as sulphate. The sulphate precipitate was converted to carbonate and dissolved in nitric acid. ²³⁴Th and ²³⁴Pa were eliminated by synergistic solvent extraction using tri-n-butyl phosphate and thenoyl trifluoroacetone extractant mixture in xylene. An iron scavenging step was included to remove any residual impurities. Finally, strontium is precipitated as SrC₂O₄^. H₂O. The separated ⁹⁰Sr activity was followed to check the equilibrium growth of ⁹⁰Y.     

Extraction of Microamounts of Yttrium from Strontium in a Water-Nitrobenzene System

A rapid extraction separation of trace amounts of yttrium from strontium with a nitrobenzene solution of sodium dicarbollylcobaltate (NaDCC) in the presence of polyethylene glycol having mean relative molecular weight 400 (PEG 400) and tetrasodium salt of ethylenediamine-N,N,N,N-tetraacetic acid (Na₄L) in the aqueous phase was developed. The separation factor (Sr/Y) was substantially higher than 10⁶. This water-nitrobenzene extraction system can be applied for the efficient separation of carrier-free ⁹⁰Y from a ⁹⁰Y/⁹⁰Sr generator.     

Preparation of 90Y by the 90Sr-90Y Generator for Medical Purpose

The production of ⁹⁰Y by ⁹⁰Sr-⁹⁰Y generator was studied. ⁹⁰Sr was adsorbed on a column with Aminex A-5 resin. The daughter radionuclide ⁹⁰Y was eluted with 0.7M -hydroxyisobutyrate (-HIB, pH 5.4). Radionuclidic, radiochemical and chemical purities were >98% and yield >85%. After converting into chloride form ⁹⁰YCl₃-solution (pH:1) was used for preparing injectable yttrium citrate and labeling some other radiopharmaceuticals. Furthermore, a fast ITLC-method for the determination of ⁹⁰Sr in ⁹⁰Y-eluate was developed.     

An improved method FO the determination of90Sr in large samples of seawater

The determination of⁹⁰Sr in large sample of seawater by its daughter product⁹⁰Y by means of solvent extraction with bis-2-ethylhexyl-phosphoric acid (HDEHP) ini n-heptane leads to²³⁴Th contamination. Two methods are described by which the²³⁸U daughter product²³⁴Th is separated from the Y³⁺ samples, either by a cation exchanger procedure or by a co-recipitation with Zr₃(PO₄)₄.     

Separation of microamounts of yttrium from strontium by using nitrobenzene solution of sodium dicarbollylcobaltate in the presence of 18-crown-6

A rapid extraction separation of trace amounts of yttrium from strontium with a nitrobenzene solution of sodium dicarbollylcobaltate (NaDCC) and 18-crown-6 in the presence of tetrasodium salt of ethylenediamine-N,N,N",N"- tetraacetic acid (Na₄L) in the aqueous phase was developed. The separation factor a(Sr/Y) was substantially higher than 10⁶. This water-nitrobenzene extraction system can be applied for efficient separation of carrier-free ⁹⁰Y from ⁹⁰Sr/⁹⁰Y generator.     

Trennung des Strontiums von Yttrium (90Sr/90Y) mit Anionenaustauscher-Sulfaten

Zusammenfassung Die selektive Fällungssorption von Strontium an Dowex-I-Sulfat im Säulenverfahren als SrSO₄ aus 50%ig methanolischer Lösung erlaubt die rasche Gewinnung von fremdstrahlungsfreiem Yttrium-90 aus dem Zerfallsprozeß . Die Kontrolle des Trenneffektes erfolgt durch Bestimmung der Halbwertszeit des ⁹⁰Y. Je nach Länge der Austauscherschicht kann unter Beachtung der Bildungsschnelligkeit von ⁹⁰Y dieses mehrfach entnommen werden.

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Summary Selective precipitating Sorption of strontium as SrSO₄ on Dowex-I-sulphate in a column operation, using aqueous methanol solution (11), permits the isolation of pure ⁹⁰Y, produced by the decay process . The effect of separation may be controlled by determination of the half-life of ⁹⁰Y. Taking into account the velocity of formation ⁹⁰Y can be obtained several times according to the length of the ion-exchanger column.

     

Bestimmung von90Sr auf der Ionex-Säule in Milch und Knochen Unter Berücksichtigung der Komplexen Eigenschaften Einiger Reagenzien

The determination of⁹⁰Sr is extremely difficult in biological materials by chemical meth ods owing to the quantity of calcium associated. The problem consists of the quantitative removal of calcium and of the selective extraction of⁹⁰Sr using strontium carrier. It can be solved by precipitation and extraction methods, or by ion exchange chromatography. Following our previous works, experimental evidence is presented using ion exchange technique for these purposees, where complex compounds are used as eluents for calcium removal. For the determination of⁹⁰Sr in milk and bones, calcium was removed with 1,2-diamino-cyclohexane-N,N,N′,N′-tetraacetic acid (CyDTA) eluent from Amberlite IR-120 column. Our results show that compounds of chelatone type used as eluents with a strong acidic cation exchanger column are the most convenient, for they prefer to compound with ligands of weaker or mean complexibility (hydrochloric acid, citric acid and lactic acid).      

Radiochemical determination of 90Sr and 86Sr in soil

Summary A modified HCl-leach method for the radiochemical ⁹⁰Sr and ⁸⁹Sr determination in soil has been developed. The sample is leached by HCl in the presence of the Sr-carrier. Then bi- and trivalent ions are separated by a combination of complexation and ion exchange. The separation of strontium and calcium is performed by fuming nitric acid. After further purification, strontium carbonate is precipitated and the activity of ⁹⁰Sr and ⁸⁹Sr is measured. ⁹⁰Sr determined by the isolation of ⁹⁰Y and by measuring its activity. The ⁹⁰Sr and ⁸⁹Sr content in soil is calculated from the measured activities of yttrium oxide and strontium carbonate by considering the counting efficiencies for ⁹⁰Y, ⁹⁰Sr and ⁸⁹Sr beta rays, the chemical yields of strontium and yttrium and the time of ⁹⁰Y growth from ⁹⁰Sr.

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Radiochemische Bestimmung von ⁹⁰Sr und ⁸⁹Sr in Boden

Zusammenfassung Eine modifizierte Auslaugungsmethode für die radiochemische Bestimmung von ⁹⁰Sr und ⁸⁹Sr im Boden wurde entwickelt. Die Probe wird in HCl in Gegenwart des Sr-Trägers ausgelaugt und die zwei- und dreiwertigen Ionen dann durch eine Kombination von Komplexierung und Ionenaustausch getrennt. Die Strontiumtrennung von Calcium erfolgt mit rauchender Salpetersäure. Nach weiterer Reinigung wird SrCO₃ gefällt und die Aktivität von ⁹⁰Sr und ⁸⁹Sr bestimmt. ⁹⁰Sr wird durch Isolierung und Zählung von ⁹⁰Y ermittelt. Der ⁹⁰Sr- und ⁸⁹-Sr-Gehalt im Boden wird aus der Aktivität von Y₂O₃ und SrCO₃ unter Berücksichtigung der Zählausbeute für ⁹⁰Y-, ⁹⁰Sr- und ⁸⁹-Sr-beta-Strahlen, aus der gravimetrischen Bestimmung von Strontium und Yttrium und aus der Zeit der ⁹⁰Y-Entstehung aus ⁹⁰Sr bestimmt.

     

90Sr in lake sediments

For a better understanding of the behaviour of⁹⁰Sr in aquatic systems, this -emitter has been determined in the different layers of a lake sediment core which has been previously dated using the well established²¹⁰Pb dating method. For this, a radiochemical technique has been developed for the isolation of strontium from the sediment samples and for its activity measurement with a low-level gas-flow proportional counter. A conservative behaviour of⁹⁰Sr in the water column remaining dissolved in the water body, can be inferred from the data obtained. Consequently, a possible⁹⁰Sr transport pathway through the outflowing waters of the lake can be deduced.     

Extraction chromatographic separation of carrier-free90Y from90Sr/90Y generator by crown ether coated silica gels

A remarkable extraction chromatographic method for the preparation of⁹⁰Y of high radiochemical purity has been developed. The generator consists of silica gel coated crown ether. It functions as a strong adsorber for⁹⁰Sr and in the meantime high purity of⁹⁰Y is eluted with a dilute solution of picric acid after a suitable period. The experiments indicated that DC18C6 coated silica gel is better than that of DB18C6 coated. The extraction capacity of strontium on 3.8% DC18C6 coated silica gel is 5.6 mg Sr/g silica gel. Yttrium is obtained with more than 95% milking yield with radionuclide purity greater than 99.9%. The extraction chromatographic generator does not change its characteristics even after 5 elutions.     

Experimentelle Bewertung Einiger FAktoren,die die90Sr-Bestimmung in Milch und Knochen auf dem Prinzip der Fällung Wesentlich Beeinflussen

A survey is given on the basic factor affecting the determination of⁹⁰Sr in milk and bones by removal of the excess calcium by precipitation. Strong co-precipitation of calcium and strontium takes place using fuming nitric acid, potassium hexacyano-ferrate, EDTA, ethanol-ether mixture and butanol-(1) due to partial precipitation, recrystallization and adhesion processes where thepH value of the environment plays an improtant role. The obtained results show very limited applicability of these agents for the determination of⁹⁰Sr in biological materials because of low accuracy and reproducibility. This conclusion is especially valid for the method of rapid determination of⁹⁰Sr with EDTA according toWelford andSutton. In this work a method is given for the determination of⁹⁰Sr in milk and bones using potassium hexacyanoferrate.      

An electrochemical pathway to prepare circular planar 90Sr/90Y sources for the calibration of surface contamination monitors

In this communication, we describe a novel method to prepare circular planar ⁹⁰Sr/⁹⁰Y sources (? = 16 mm) exploiting the intrinsic properties of the anodized titanium to electro-deposit predicted quantity of ⁹⁰Sr activity from an aqueous solution. The influences of various experimental parameters such as pH of the electrolyte, applied current density, electrodeposition time and carrier strontium concentration were thoroughly investigated to arrive at a condition resulting optimal deposition of the ⁹⁰Sr/⁹⁰Y activity on the substrate. An optimized electrochemical procedure to prepare ~3.7 MBq (~0.1 mCi) of circular planar ⁹⁰Sr/⁹⁰Y sources commensurate with regulatory safety requirement has been the positive outcome.     

A new method for the carrier-free production of 90y from 90sr-90y mixture and 89sr from neutron-irradiated y2o3

The extraction of strontium(II) and yttrium(III) ions from aqueous solutions at various pH values into methyl isobutyl ketone containing I-phenyl-3-methyl-4-caprylpyrazolone-5 is described. Quantitative extraction of Sr and Y at pH 8.6–10 and pH 2.8–5.4 respectively is utilized for the carrier-free production of ⁹⁰Y from ⁹⁰Sr–⁹⁰Y mixtures and ⁸⁹Sr from neutron-irradiated yttrium oxide. A clean separation of these elements from each other and more than 95% calculated activities were recovered     

The simple radiochemical determination of 90Sr in environmental solid samples by solvent extraction

Determination of ⁹⁰Sr in environmental solid samples is a challenging task because of the presence of so many other radionuclides in samples of interest. This problem was dealt with by radiochemical separation of strontium followed by yttrium separation and Cerenkov counting of the high-energy ??-particle emissions of ⁹⁰Y in order to quantitate ⁹⁰Sr. In this work, an improved method is described for the determination of ⁹⁰Sr in soil samples, through the separation of the daughter ⁹⁰Y at equilibrium. The procedure is based on the HDEHP solvent extraction in combination with liquid scintillation spectrometry (LSS). A low background Quantulus has been optimized for low level counting of Cerenkov radiation emitted by the hard ??-emitter ⁹⁰Y. The analytical quality of the method has been checked by analyzing IAEA Soil-375 reference materials. The analytical method has also been successfully applied to the determination of ⁹⁰Sr for moss-soil samples in inter-laboratory exercises through IAEA??s ALMERA network. The chemical recovery for ⁹⁰Y extraction ranged from 80 to 85% and the counting efficiency was 73% in the window 25?C400 keV.     

Methodology for determination of 89Sr and 90Sr in radiological emergency: I. Scenario dependent evaluation of potentially interfering radionuclides

Early determination of ⁸⁹Sr and ⁹⁰Sr in radiological emergency is hampered by the presence of interfering short-lived fission products. In this study, three commonly used radioanalytical strategies for ⁸⁹Sr and ⁹⁰Sr were evaluated theoretically considering their suitability in a nuclear explosion scenario. The methods were evaluated with respect to the need for decay time of interfering short-lived strontium and yttrium isotopes, and reduction of other known interfering nuclides prior to measurement. The strategy shown to be most successful included initial separation of strontium and determination of ⁸⁹Sr, followed by an yttrium separation and counting of ⁹⁰Y. ⁸⁹Sr and ⁹⁰Sr could be determined about 5 and 9 days after a nuclear explosion, respectively.     

Studies on soil samples mineralization conditions preceding the determination of 90Sr

Some results of the extraction of strontium and yttrium from soil samples by concentrated nitric acid are described. The concentration of Sr and Y in the solid was determined by XRF method. The results obtained allowed to elaborate the conditions of acid leaching and to propose an analytical procedure for the determination of ⁹⁰Sr in samples without their total dissolution.     

Beta-spectroscopic separation of90Sr,90Y and89Sr with a scintillation detector

A -spectroscopic method for measurement of the isotope ratios and absolute activities of⁹⁰Sr,⁹⁰Y and⁸⁹Sr with an organic scintillator is described and tested. The correction factors for absorption in the sample and the detector window are calculated. The method can be used for rapid estimation of ratios and absolute activities of pure -emitters after a nuclear accident.Supported in part by the International Atomic Energy Agency, RC5633 and the National Fund for Scientific Research (Bulgaria).     

Bestimmung des Gehaltes an90Sr und89Sr in Proben tierischer und pflanzlicher Herkunft

A method is described for the determination of⁸⁹Sr and⁹⁰Sr in samples of plant and animal origin. The Rehak-Feddersen method was modified to measure⁹⁰Sr. Modification was made in the sample preparation and in the toluene-HDEHP [di(2-ethylhexyl)phosphoric acid] extraction. After the extraction of yttrium, strontium is separated with nitric acid and—calculating with a correction factor—⁸⁹Sr can directly be determined. Namely,⁸⁹Sr can be measured in an aqueous solution by a liquid scintillation technique with an efficiency of 30% while⁹⁰Sr with 1.4% only. Quenching of the solution—depending on the composition—which may influence the measurement of⁹⁰Y and⁸⁹Sr was also examined. Detection limits and reproducibilities are given. Finally, evaluation of the experimental data is reported.      

Separation of microamounts of yttrium from strontium by using sodium dicarbollylcobaltate, Slovafol 909 and ethylenediamine - N, N, N', N'-tetraacetic acid in the water - nitrobenzene extraction system

Summary A rapid extraction separation of trace amounts of yttrium from strontium by a nitrobenzene solution of sodium dicarbollylcobaltate (NaDCC) in the presence of p-nonylphenylnonaethylene glycol (Slovafol 909) and tetrasodium salt of ethylenediamine - N,N,N',N' - tetraacetic acid (Na₄L) in the aqueous phase was developed. The separation factor a(Sr/Y) was substantially higher than 10⁵. This water-nitrobenzene extraction system can be applied for the efficient separation of carrier-free ⁹⁰Y from ⁹⁰Y/⁹⁰Sr generator.