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.     

Atmospheric depositional fluxes of cosmogenic <Superscript>32</Superscript>P, <Superscript>33</Superscript>P and <Superscript>7</Superscript>Be in the Sevastopol region

⁹⁰Y was separated from ⁹⁰Sr using an extraction chromatographic resin consisting of 4, 4′(5′)-bis-t-butylcyclohexano-18-crown-6 (DtBuCH₁₈C₆), 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) amide (C₂mimNTf₂), and a polymer (Amberlite XAD-7). Ionic liquid was introduced into the column to improve the separation efficiency. The column showed an excellent performance for the separation of Y from Sr. After the separation, the ratio of ⁹⁰Sr/⁹⁰Y was <2.0 × 10^?5; the column was recycled for >18 times. This study provides preliminary results on columns to produce ⁹⁰Y with a high purity in radiopharmaceuticals.     

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.     

Separation of yttrium from strontium in the aqueous phase of the water/nitrobenzene extraction system

A rapid separation for carrier-free ⁹⁰Y in the aqueous phase of the water/nitrobenzene extraction system from an ⁹⁰Y/⁹⁰Sr generator was proposed. After two-stage extraction separation, chemical yield of ⁹⁰Y in the final aqueous phase was roughly 80%, while ⁹⁰Sr radionuclide impurity in this phase containing carrier-free ⁹⁰Y was 10^-6%.     

The solvent extraction of carrier-free90Y from90Sr with crown ethers

A simple solvent extraction method has been developed for the separation of⁹⁰Y from⁹⁰Sr. Crown ether dissolved in chloroform was used as a selective reagent and organic picrate anion was chosen as a counter ion. The effect of various factors on the extraction separation of strontium and yttrium in the system have been studied. The extraction equilibrium constant of strontium logK _ex=9.15 was obtained from the study of the distribution coefficient versus the crown ether concentration. The separation method was simple, resulted high purity (>99.9%) and quantitative yield, and took less than half an hour.     

Mathematical modeling of separation of microamounts of strontium from yttrium in water - HCl -nitrobenzene - 15-crown-5 - hydrogen a dicarbollylcobaltate extraction system</p> </p>

Summary A rapid separation of microamounts of Sr²⁺ from Y³⁺ using HCl, 15-crown-5 (15C5) and hydrogen dicarbollylcobaltate (H⁺B^-) in the two-phase water - nitrobenzene extraction system was developed. The reached separation factor a(Sr/Y) was approximately 10. ^5.4</p> __</p>     

Separation of yttrium from strontium in the aqueous phase of the water/nitrobenzene system

A rapid separation of carrier-free ⁹⁰Y in the aqueous phase of the water/nitrobenzene extraction system from an ⁹⁰Y/⁹⁰Sr generator is proposed. After a three-stage extraction, the chemical yield of ⁹⁰Y in the final aqueous phase was almost 90%, while the ⁹⁰Sr radionuclide impurity in this phase containing carrier-free ⁹⁰Y was about 10^–10%.     

Variations in the gross alpha and beta activity in surface waters at the Atomic Weapons Establishment Aldermaston (UK)

N,N,N′,N′-tetra-2-ethylhexyldiglycolamide (T2EHDGA) has been used for the preferential extraction of ⁹⁰Y from its mixture with ⁹⁰Sr from HNO₃ as well as HCl medium. The separation efficiencies have been found out under varying experimental conditions. The extracted species were determined from T2EHDGA concentration variation experiments carried out at 3 M nitric acid as well as HCl and were found out to be Y(X₃)₃·3(TEHDGA)_(o) for both the extraction systems, where X = NO₃ ⁻ and Cl⁻, respectively. Comparison of the T2EHDGA and TODGA based separation methods is also made. In order to avoid third phase formation, iso-decanol has been used as the modifier in all the studies. The modifier content was optimized to 30% for 4 M HCl and 20% for 6 M HNO₃ as the feed aqueous phases. Separation schemes were developed for the separation of carrier free ⁹⁰Y and the purity was checked by the half-life measurement method.     

Studies on Separation of 90Y and 90Sr Separation from Hydrochloric Acid Solutions Using TODGA as the Extractant by SLM Method

Yttrium-90 is an important radionuclide known for its therapeutic application in nuclear medicine. Solvent extraction studies with N,N,N’,N’-tetra-octyldiglycolamide (TODGA) has shown that Y(III) is well extracted in 6 M HCl while at the same time, extraction of Sr(II) is very low leading to a separation factor (DY/DSr = 60,000). This property of TODGA can be exploited for the separation of Y from Sr. The aim of this present work is to produce carrier free ⁹⁰Y by using Supported Liquid Membrane (SLM) based separation of Y and Sr with TODGA as the carrier. Solvent extraction studies with various diluents viz. 1-decanol, xylene, MIBK, chloroform etc. indicated that xylene and n-dodecane are most suitable as S.F. >50,000 are obtained. Based on the results, a SLM based separation scheme was developed using 0.1 M TODGA in xylene loaded on a microporous PTFE membrane as a polymeric support and 6 M HCl as feed and 0.01 M HCl as strip phase. The results appear promising for the development of SLM based Y-90 generator. The purity of the product was ascertained by the half life method.     

The use of liquid scintillation spectrometry for the determination of radionuclidic purity of 90Y from a radiochemical 90Y/90Srgenerator

Summary An extraction technique for the separation of ⁹⁰Sr from a high excess of⁹⁰Y has been developed. This procedure can be used for the determination of trace amounts of⁹⁰Sr in⁹⁰Y prepared by a radiochemical⁹⁰Y/⁹⁰Sr generator by liquid scintillation.     

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     

Extraction of radiostrontium from the mixture of radionuclides in milk using dicarbolide of cobalt

The possibilities of radiostrontium extraction from milk after the isolation of radiocesium were investigated. The polyhedral complex of the type H⁺[(π-/3/-1,2-C₂B₉H₁₁)₂Co⁻], further referred to as dicarbolide-H⁺, in nitrobenzene was used for the extraction. The increase of values and larger differentiation of distribution ratios in the extraction of ion associates of radionuclides were achieved by hydrophobizing with polyethyleneglycol (PEG). The changes of the distribution ratios of⁹⁰Sr,⁸⁹Sr and⁹⁰Y with PEG concentration were studied, and ranges of the highest synergic effect, changing with different extraction agent concentrations in extraction from water solutions and a fresh milk were determined. The influence of milk dilution and nitric acid concentration upon the value of distribution ratio in radiostrontium extraction using dicarbolide-H⁺ and the optimum PEG concentration were investigated. Under suitably selected conditions of radiostrontium isolation, the distribution ratios of some potential contaminants were determined. The influence of nonisotopic carrier Ca²⁺ upon radiostrontium extraction was examined. The possibilities of purification of isolated radiostrontium using reextraction were investigated. A selective and quick analytical procedure was suggested for radiostrontium isolation after the separation of radiocesium from a mixture of fission and activated radionuclides in milk using extraction by dicarbolide-H⁺. The chemical yield is about 98% and⁹⁰Sr is determined by liquid scintillation technique.     

Seasonal variations of atmospheric210Pb and7Be concentrations at Kumamoto, Japan and their removal from the atmosphere as wet and dry depositions</p> </p>

Summary A relatively simple chemical separation procedure has been developed for the simultaneous determination of⁸⁹Sr and ⁹ 0Sractivities in water samples and on aerosol-filters of the Nuclear Power Plant (NPP) Paks origin. The procedure combines the cation-exchange chromatographic (Dowex 50 WX 8 resin) and solid phase extraction (EIChroM Sr.Spec?, DC18C6 crown ether) steps. The beta-radiation of radionuclides can be measured directly after the chemical separation by LSC. The activities of⁸⁹Sr,⁹⁰Sr and⁹⁰Y are calculated from an over determined set of equations using a method of constrained optimization technique. The equations are based on LSC measurements performed in three counting windows plus the⁹⁰Sr-⁹⁰Y decay law. The chemical yield of strontium is determined by ICP-AES. The lowest limits of detectable activity, for the measurement time of 600 minutes, are 30 mBq/sample and 18 mBq/sample for⁸⁹Sr and⁹⁰Sr, respectively.     

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.     

Rapid determination of 89,90Sr in wide range of activity concentration by combination of yttrium, strontium separation and Cherenkov counting

The methodology for the rapid determination of ^89,90Sr in wide range of activity concentration is given. Methodology is based on simultaneous separation of strontium and yttrium from samples by mixed solvent anion exchange chromatography, mutual separation of ^89,90Sr from ⁹⁰Y by hydroxide precipitation and quantitative ^89,90Sr determination by Cherenkov counting within 3 days. It is shown that Y and Sr can be efficiently separated from alkaline, alkaline earth and transition elements as well as from lanthanides and actinides on the column filed by strong base anion exchanger in nitrate form and 0.25 M HNO₃ in mixture of ethanol and methanol as eluent. Decontamination factor for Ba, La and other examined elements except calcium is low and can not affect quantitative determination in predictable circumstances. Methodology for quantitative determination by Cherenkov counting based on following the changes of sample activity over time is described and discussed. It has been shown that ^89,90Sr can be determined with acceptable accuracy when ⁸⁹Sr/⁹⁰Sr ratio is over 10:1 and that separation of Y enables reliable determination of ⁸⁹Sr and ⁹⁰Sr in wide range of ⁸⁹Sr/⁹⁰Sr ratios (60:1) and in some cases in presence of other yttrium and strontium isotopes. The methodology was tested by determination of ^89,90Sr in Analytics crosscheck samples (nuclear waste sample) and ERA proficiency testing samples (low level activity samples). Obtained results shows that by using of low level liquid scintillation counter it can be possible to determine ⁸⁹Sr and ⁹⁰Sr in wide range of concentration activity (1–1,000 Bq/L/kg) with uncertainty below 10% within 2–3 days. Results also show that accuracy of determination of ⁸⁹Sr (and ⁹⁰Sr) strongly depends on the determination of difference between separation and counting time when activity ratio of ⁸⁹Sr/⁹⁰Sr is high. Examination the influence of media and vial type on background radiation and counting efficiency has shown that lowest limit of determination can be obtained by using of HNO₃ in plastic vials as counting media, because in this combination figure of merit is maximized. For the recovery of 50% and 100 min of counting time estimated MDA is 55 Bq and 90 Bq for ⁹⁰Sr and ⁸⁹Sr, respectively. Analysis of combined uncertainty shows that it mainly depends on uncertainty of efficiency and recovery determination, uncertainty of activities determination for both isotopes and level of background radiation.     

Studies on the separation of 90Y from 90Sr by solvent extraction and supported liquid membrane using TODGA: role of organic diluent

Solvent extraction and supported liquid membrane transport studies on Y(III) and Sr(II) were carried out using both nitric as well as hydrochloric acid feed conditions using N,N,N′,N′-tetra-octyldiglycolamide (TODGA) in several organic diluents. The solvent extraction studies indicated extremely large separation factor (SF) values with chloroform, carbon tetrachloride, 1-decanol and hexone when 6 M HNO₃ was used as the feed. On the other hand, the SF values were 1–2 orders of magnitude lower when the nitric acid concentration was 3 M HNO₃. Significantly large SF values were also obtained from 6 M HCl when xylene, carbon tetrachloride, n-dodecane and hexone were used as the diluent. Though mass transfer was not very promising in the supported liquid membrane studies with most of the diluent systems, quantitative Y(III) transport was observed with 0.1 M TODGA in xylene with negligible Sr(II) transport suggesting possibility of obtaining carrier free ⁹⁰Y. The purity of the radiotracer was checked by half-life method.     

Rapid determination of 90Sr/90Y in water samples by liquid scintillation and Cherenkov counting

Strontium-90 (⁹⁰Sr) is a ubiquitous contaminant at nuclear facilities, found at high concentrations in spent nuclear fuel and radioactive waste. Due to its long half-life and ability to be transported in groundwater, an accurate method for measuring ⁹⁰Sr in water samples is critical to the monitoring program of any nuclear facility. To address this need, a rapid procedure for sequential separation of Sr/Y was developed and tested in groundwater samples collected from an area of riverbed affected by a ⁹⁰Sr groundwater plume. Sixteen samples, plus spike and water blanks, were analyzed. Five different measurements were performed to determine the ⁹⁰Sr and yttrium-90 (⁹⁰Y) activities in the samples: direct triple-to-double-coincidence ratio (TDCR) Cherenkov counting of ⁹⁰Y, liquid scintillation (LS) counting for ⁹⁰Sr following radiochemical separation, LS counting for ⁹⁰Y following radiochemical separation, Cherenkov counting for ⁹⁰Y following radiochemical separation and LS counting of the Sr samples for ⁹⁰Y in-growth. The counting was done using a low-level Hidex 300SL TDCR counter. Each measurement method was compared for accuracy, sensitivity and efficiency. The results following Cherenkov counting and radiochemical separation were in very good agreement with one another.     

The separation of daughter nuclides from90Sr−90Y and140La−140Ba systems by thin-layer chromatographic methods

The separation of daughter nuclides in the carrier-free state from⁹⁰Sr?⁹⁰Y and¹⁴⁰Ba?¹⁴⁰La aqueous solution systems was performed by thin-layer chromatographic methods. (1) When a silica gel adsorbent and a developer of 1N NaCl, KCl, NH₄Cl, CaCl₂, SrCl₂ or BaCl₂ solutions was employed,⁹⁰Y and¹⁴⁰La were retained at the origin, while⁹⁰Sr and¹⁴⁰Ba advanced with the developer front. Addition of gypsum as binder to the silica gel prevented the separation of the¹⁴⁰Ba?¹⁴⁰La system, retaining both components at the origin. (2) When the¹⁴⁰Ba?¹⁴⁰La system was developed with water on a silica gel adsorbent containing 5% of gypsum, which was treated with various concentrations of nitric acid, the Rf value of¹⁴⁰La increased with the concentration of nitric acid used, reaching a maximum of 0.98 at 0.1 N. The Rf value then decreased on the further increase of the concentration of nitric acid. When the same process was applied to the⁹⁰Sr?⁹⁰Y system, there was no separation. The radiochemical purities of⁹⁰Y and¹⁴⁰La obtained in the above two ways were more than 99%.     

Measurement of 90Sr in Marine Biological Samples

Strontium-90 (⁹⁰Sr) is one of the most hazardous radionuclides, and it contributes to radiation exposure by ingestion. The routine determination of ⁹⁰Sr in marine biological samples is highly desirable given the development of the nuclear power industry. A fast, simple, and low-detection-limit method was developed for the measurement of ⁹⁰Sr in marine biological samples based on determining ⁹⁰Y by means of coprecipitation and solvent extraction with bis-2-ethylhexyl-phosphoric acid (HDEHP) in n-heptane. The interfering ²¹⁰Bi is removed using Bi₂S₃ precipitation. The separation and purification of eight samples per day can be accomplished through this method. The detection limit of ⁹⁰Sr for this method is 0.10 Bq/kg (ash weight). The radiochemical procedure was validated by fitting the decay curve of the sample source and by the determination of ⁹⁰Sr standards.     

Separation of bulk Y from 89Y(n,p) produced 89Sr by extraction chromatography using TBP coated XAD-4 resin

⁸⁹Sr was produced using the ⁸⁹Y(n, p) ⁸⁹Sr reaction by irradiating yttria target in the fast breeder test reactor (FBTR). An analytical scale procedure was standardized for the removal of the bulk target yttrium by solvent extraction using the tri-n-butyl phosphate (TBP). The final purification of ⁸⁹Sr source was carried out by ion exchange chromatography. However, extraction chromatography is preferred to solvent extraction due to its low waste generation and ease of operation. This paper reports the separation of Sr from bulk Y and other radioactive impurities produced during irradiation by extraction chromatography using TBP coated XAD-4 resin. Initially the separation procedure was standardized using ⁸⁵Sr and ⁸⁸Y tracers. The ⁸⁹Sr in the dissolver solution of the irradiated yttria target was separated under the same standardized conditions. The study established the separation of Sr from Y in the dissolver solution of the irradiated target yttria by the TBP coated XAD-4 column. However the evaluation of the column after every use for about three separation studies exhibited the reduction in its breakthrough capacity for yttrium.