Authors:Veronika Drábová, Jana Strišovská, Lívia Dvorská, and Jozef Kuruc
Two separation techniques for strontium determination using AnaLig® Sr01 molecular recognition technology and extraction chromatography Sr® resin were tested. The methods performance was investigated by analysis of NPL (High Alpha–Beta 2003) intercomparison sample.
The results obtained for both procedures were compared in terms of activities and recoveries. Data analysis proved a good
agreement with the reference values. The AnaLig® Sr01 separation method for 90Sr determination was successfully validated with the same performance as the Sr® resin method.
Authors:A. Laissaoui, S. Mulsow, M. Benmansour, J.J. La Rosa, and M. IbnMajah
An improved and rapid method is described for the determination of 90Sr in environmental 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 QuantulusÔ has been optimized for low level counting of Cerenkov radiation emitted by the hard b-emitter 90Y. The counting efficiency was 60% and the background 0.53 cpm. The reliability and reproducibility of the method have been checked using IAEA reference materials. The chemical recovery for 90Y extraction ranges from 83 to 90%.
Authors:G. Lujaniene, A. Plukis, E. Kimtys, V. Remeikis, D. Jankünaite, and B.I. Ogorodnikov
The vertical distribution of 137Cs, 90Sr, 239,240Pu, 238Pu and 241Am was determined in soil samples collected from the Chernobyl exclusion zone in 1994. The results show very close distribution profiles for all radionuclides, with about 90% of the total activity of each nuclide lying between the surface and the fourth centimeter. Sequential extraction methods were used to determine the association of radionuclides in soil. The data on vertical distribution of radionuclide species were used to calculate their vertical migration parameters.
Authors:Silvia Dulanská, Boris Remenec, Dušan Galanda, Mojmír Němec, and Lívia Dvorská
In this paper rapid separation methods for strontium determination using molecular recognition technology products 3M Empore™
Sr disc, AnaLig® Sr-01 and extraction chromatography Sr® Resin were presented and statistical tested. The methods performance was investigated by analysis of NPL (High Alpha–Beta
2003) and (High Alpha–Beta 2005) intercomparison samples. The presented results were evaluated as correct for all experimental
data. We used linear regression (with regression diagnostics), t test and the mean of variable using 90Sr with 3M Empore™ Sr disc, AnaLig® Sr-01 and Sr® Resin.
Radioactivity of 90Sr and 137Cs in several species of herbs collected at Fajsawice and Góra Puawska located in Lublin (Poland) region was examined. Depending on the type of herb the radioactivity of strontium ranged from 0.004 to 1.808 Bq/kg dry weight whereas that from cesium varied from 0.053 to 9.853 Bq/kg. Calculated transfer factors of the radioisotopes in the plants studied revealed much stronger accumulation of strontium than cesium. Concentration of calcium and potassium in these plants has no influence on the concentration of measured radioisotopes.
Authors:J. W. Mietelski, L. Kitowski, P. Gaca, S. Grabowska, E. Tomankiewicz, and P. Szwałko
The present study focused on analyzing samples of bones, livers and kidneys of European white-tailed eagles (Haliaëtus albicilla) and lesser-spotted eagle (Aquila pomarina). Bone samples were collected for both species, from 7 and 2 individuals, respectively, whereas liver and kidney samples
for white-tailed eagle species only, 2 and 1 individuals, respectively. The samples were analyzed for the presence of gamma-emitters
and then for 90Sr, 238Pu, 239+240Pu and 241Am. The applied radiochemical method is presented. Activity concentration in ashen bones (600 °C) for 90Sr ranged from 4.6±1.2 to 31.0±2.5 Bq/kg, for 239+240Pu from <1.7 to 21±4 mBq/kg, for 238Pu from <2.7 to 6.5±1.3 mBq/kg and for 241Am from <1.2 to 6.5±4.4 mBq/kg. Relatively high 239+240Pu activity concentration of 78±9 mBq/kg (for fresh weight) was recorded in a single kidney sample. The liver samples showed
activities of magnitude at least one order lower. No clear correlations were found between the activities of different radionuclides.
Authors:H. Bjørnstad, H. Lien, Yu-Fu Yu, and B. Salbu
Low level90Sr in environmental and biological samples is determined using a combined HDEHP solvent extraction-liquid scintillation procedure. Yttrium-90 is selectively extracted from nitric acid solution into 5% di(2-ethylhexyl) phosphoric acid (HDEHP) in toluene, and90Y in the organic phase is measured directly using an ultra low level liquid scintillation spectrometer.The working program of the Quantulus counter has been optimized. As the counting efficiency using liquid scintillation counting is high and the stripping and precipitation of Yttrium-90 oxalate is omitted, this procedure is simpler and more timesaving than traditional methods. The chemical recoveries of90Y were 85.1% for soil, 75.7% for milk and 65.3% for bone. The detection limit is 8 mBq.
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.
Strontium-90, plutonium and americium activity concentrations in a few samples of forest soils, some species of mushrooms and fern leaves have been determined. These results are compared with cesium activity concentrations in the same materials obtained in a previous work. Radiochemical procedures are described. The origin of the contamination (Chernobyl accident or nuclear test explosion release) is discussed. The90Sr activity concentration ranges from 0.6 Bq/kg (mushroom samples) to 48.4 Bq/kg (fern leaves). For239+240Pu, it ranges from not detected above background (mushrooms, fern) to 10.8 Bq/kg (humus layer of forest soil). The maximum concentration of241Am is found to be 2.4 Bq/kg (humus sample) and for238Pu it is 0.85 Bq/kg (also in the humus sample).
A simple ion exchange procedure for clean separation of the biomedically important radionuclide,90Y, in the equilibrium mixture,90Sr–90Y, has been demonstrated. Separation of90Y in the carrier-free state has been achieved by preferential elution of the radiotracer through a cation exchange resin column of Dowex-50W-X8 with freshly prepared Na-ascorbate solution of <1% concentration at pH7. The radionuclidic purity of the separated90Y has been verified by taking recourse to the studies of beta decay curves. The procedure developed has the added advantage that the complexing reagent, ascorbic acid, itself has got its own biomedical importance as vitamin C and the technique can also conveniently be used as a generator for the isotope90Y.