共查询到20条相似文献,搜索用时 500 毫秒
1.
Jia Guogang C. Testa D. Desideri F. Guerra C. Roselli 《Journal of Radioanalytical and Nuclear Chemistry》1998,230(1-2):21-28
A sensitive and reliable metbod for the sequential separation and determination of plutonium,241Am and90Sr in soil samples was developed. Plutonium was separated by a Microthene-TNOA column. Then90Y (for90Sr determination) was separated from americium by a HDEHP column after elimination of large amounts of interfering stable
or radioactive nuclides (iron,210Bi and210Po etc.) by an oxalate precipitation and a Microthene-TNOA column. Finally americium was purified by another HDEHP column
and a PMBP-TOPO extraction. A special attention was paid to the decontamination of Pu and Am from210Po and of90Y from210Bi; the relevant decontamination factors resulted greater than 105, 106 and 104 respectively. The detection limits were 1.2 mBq/kg for Pu and 1.7 mBq/kg for241Am and 0.32 Bq/kg for90Sr. The procedure was checked by analyzing three certified samples supplied by IAEA. Some Italian soil samples were also analyzed
giving average yields of 84.9±7.2% for Pu, 57.8±3.2%for Am and 96.7±1.6% for Y; the239+240Pu,238Pu,241Am and90Sr contents (Bq/kg) ranged from 0.347 to 1.53, from 0.013 to 0.048, from 0.126 to 0.556 and from 2.89 to 11.6 respectively
and the average ratios were 0.037±0.017 for238Pu/239+240Pu, 0.357±0.040 for241Am/239+240Pu and 7.0±1.2 for90Sr/239+240Pu. 相似文献
2.
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. 相似文献
3.
M. Pimpl 《Journal of Radioanalytical and Nuclear Chemistry》1995,194(2):311-318
A radiochemical procedure is described for the sensitive determination of89Sr and90Sr activity concentrations in soil and sediment samples. After leaching the sample with hydrochloric acid, Sr is separated from most of the soluble matrix constituents and Ca by solvent extraction using dicylclohexano-18-crown-6 in trichloromethane. After backextraction with a EDTA-solution (ethylene diamine tetra acetate), Sr is purified by several precipitation steps from traces of matrix constituents and radionuclides which might interfere the beta measurements of89Sr,90Sr and90Y. The detection limits are about 0.2 Bq/kg and 0.4 Bq/kg for90Sr and89Sr respectively. The procedure can be applied to all kind of environmental samples with small modifications of the sample preparation steps prior to analysis. 相似文献
4.
C. Testa D. Desideri F. Guerra M. A. Meli C. Roselli G. Jia 《Journal of Radioanalytical and Nuclear Chemistry》1998,229(1-2):23-32
Separation chemistry plays an important role when alpha-and beta-emitting natural and artificial radionuclides at low levels
must be determined in complex environmental matrices. This paper describes some separation techniques used in radioecology,
with special emphasis on extraction chromatography. The very high necessary decontamination factors are pointed out together
with the suggested techniques. The following examples are given: (a) determination of90Sr in soils in the presence of high concentration of210Bi; (b) determination of cosmogenic32P in sea water and its decontamination from234Th; (c) determination of63Ni and59Ni in liquid effluents; (d) separation techniques used for the speciation of plutonium in sea sediments and (e) plutonium
and241Am concentration and vertical distribution in mosses. 相似文献
5.
A simple method for the determination of90Sr by using thin layer chromatography on silica gel or cellulose pretreated with calcium oxalate is proposed. In these conditions a complete separation between strontium and its daughter yttrium is obtained. Radioactivity of separated elements was measured by a linear multiscanner analyzer and the results were computer processed to obtain the activity of90Sr. The method has been applied to samples of water and milk subjected to a very simple extraction procedure. Under the experimental conditions used, the detection limit is about 25 mBq of deposited radioactivity, which corresponds to about 6 Bq/l. 相似文献
6.
N. Paunescu D. Galeriu R. Margineanu A. Iorgulescu 《Journal of Radioanalytical and Nuclear Chemistry》1992,163(2):289-299
This paper presents the results of radioactivity studies of environmental factors such as surface water, sediment, aquatic vegetation and soil. The concentrations of137Cs,90Sr,3H, U, Ca, and Mg in water samples were determined by radiochemical and chemical methods. Gamma-spectrometric analyses were performed for all the samples. The analysis showed a decrease in concentrations of137Cs in water, aquatic vegetation and sediment, but a constant level of137Cs activity in soil (0–5 cm depth). The average concentrations of90Sr,3H, U, Ca and Mg were about 7 mBq/l, 11 Bq/l, 0.6 g/l 60 mg/l and 11 mg/l, respectively. 相似文献
7.
Claudia Landstetter Wolfgang Ringer Arno Achatz Christian Katzlberger 《Journal of Radioanalytical and Nuclear Chemistry》2010,286(2):435-439
90Sr was measured in environmental samples in Upper Austria in the year 2005. After the nuclear weapon tests the average deposition of 90Sr in Austria amounted to 3.3 kBq/m². In 1986 the average deposition was 0.9 kBq/m² [1]. To assess the actual condition in soil, grass and cereals 90Sr was measured in these samples. For all samples oxalate precipitation was conducted and strontium specific columns (Eichrom Industries, Inc.) were used. The calcium concentration in these samples was determined to estimate the amount of resin needed for the preparation. For grass and cereal samples columns were packed with the 100–150 μm resin to gain a lower limit of detection LLD below 2 and below 0.1 Bq/kgdry matter respectively. The prepacked 2 mL columns with particle size 100–150 μm were used for soil (LLD below 2 Bq/kgdry matter). After digestion of soil samples, hydroxide precipitation was used as an additional separation step. The 90Sr was measured by liquid scintillation counting. For quality control reasons, first the initial strontium concentration in the sample was determined then a strontium carrier solution was added and after the separation steps the chemical recovery was determined by ICP-MS. Thus, no radioactive tracer and just a small amount of the measuring solution were needed. The results are presented and discussed. These results will be used as reference for further 90Sr analyses which will be conducted in a 5 year period to detect any radiological impact of the nuclear power plant Temelin on the environment of Austria. 相似文献
8.
Ehinger S. C. Pacer R. A. Romines F. L. 《Journal of Radioanalytical and Nuclear Chemistry》1986,98(1):39-48
A method for the separation of210Pb,210Bi and210Po using spontaneous deposition has been developed. The210Bi and210Po are simultaneously removed by deposition onto nickel foil (copper and tin could also be used but less effectively) while the210Po is separated from210Bi, after dissolution of the nickel foil, by deposition onto silver foil. The effectiveness of each separation was evaluated by adding aliquot portions of each solution to a cocktail and counting with a liquid scintillation counter. Water was used as the medium to observe the Cherenkov count of the sample solution. 相似文献
9.
Ž. Grahek S. Lulić K. Košutić I. Eškinja Š. Cerjan K. Kvastek 《Journal of Radioanalytical and Nuclear Chemistry》1995,189(1):141-146
A new procedure for isolation and determination of90Sr in real natural samples is presented. It consists of bringing natural samples in a soluble form suitable for separation on an ion-exchange column, separation of calcium from strontium by means of the anion exchanger Amberlite CG-400 and 0.25M HNO3 in methanol as eluent for calcium, and the determination of90Sr using a low level -counter after elution with H2O, scavenging steps and SrCO3 precipitation. The method was tested with IAEA standards of natural samples with known contents of90Sr, and water samples, where the concentration of90Sr was previously determined by the standard IAEA procedure. The results obtained show that it is possible to isolate and determine low levels of90Sr in natural samples. The procedure is favorable because of the simple separation of radioaactive strontium without using fuming nitric acid. 相似文献
10.
P. Froidevaux J.-J. Geering J.-F. Valley 《Journal of Radioanalytical and Nuclear Chemistry》2002,254(1):23-27
A method is presented for the determination of 90Sr in environmental samples by direct milking of 90Y. Pyridine-2,6-dicarboxylic acid forms an anionic complex with yttrium which is retained on an anionic resin. Most of the matrix elements are washed out of the column as neutral or uncomplexed species and yttrium is eluted by increasing the ionic force of the eluent solution. This method gives yttrium recoveries between 65% to 85% for soil, grass, milk and bone samples with very high radiochemical purity (90Y average half-life of 66±4 hours) and a detection limit of 0.3 Bq/kg of soil. The method supports a calcium content up to 3 g per sample without any decrease in yttrium yield, allowing the measurement of milk, milk-teeth and bone samples with no concentration step in one day. 相似文献
11.
89Sr and90Sr were determined in the fallout of May 1986. The maximum values of 335 Bq/(m2.6 h) and 110 Bq/(m2.6 h) were observed on May 2 and 5. Throughout May 1986 a quantity of 860 Bq/m2 of90Sr, deposited from the fallout in the Bucharest-Mgurele area, was estimated. 相似文献
12.
N. Păunescu R. Mărgineanu A. Iorgulescu 《Journal of Radioanalytical and Nuclear Chemistry》1988,128(4):263-271
This work shows the variation of90Sr and137Cs in atmospheric fallout in the Bucharest-Mgurele area during 1986–1987. The amount of90Sr in the fallout was estimated to be about 900 Bq.m–2 in 1986 and about 9.2 Bq.m–2 in 1987. The amount of137Cs was estimated to be 13300 and 615 Bq.m–2 in 1986 and 1987, respectively. 相似文献
13.
D. Desideri F. Guerra M. A. Meli C. Testa 《Journal of Radioanalytical and Nuclear Chemistry》1995,200(5):385-396
A selective method is described for the determination of210Pb in sediments, based on the separation of the daughter210Bi by extraction chromatography with Microthene 710-tri-n-octylphosphine oxide (TOPO) and on a final source counting with a low background -counter. The average chemical yield is 92.0%. The detection limit for 2 g samples is 19 Bq kg–1. An IAEA reference sediment sample was analyzed to check the reliability of the method. 相似文献
14.
Ba and Pb radionuclides can be removed from Sr in aqueous solution in both sodium acetate and acetic acid, containing 20 mg Sr carrier, by stirring with small (0.1–0.5 g) amounts of solid manganese dioxide. In tracer experiments85Sr was separated with only small losses from133Ba and210Pb by separation factors of 87 and 135, respectively. The separation factor is defined here as the % of the initial85Sr activity/ % of the initial133Ba or210Pb activity remaining in the aqueous phase after MnO2 contact. The applicability of this technique for removing Ba and Pb radionuclides in the analysis of90Sr in environmental samples (especially milk) is discussed. 相似文献
15.
N. Matsuoka T. Umata M. Okamura N. Shiraishi N. Momoshima Y. Takashima 《Journal of Radioanalytical and Nuclear Chemistry》1990,140(1):57-73
A radioanalytical procedure has been developed for the determination of99Tc in environmental samples. The procedure consists of precipitation, solvent extraction, ion exchange, electrodeposition and radiation measurement. Rhenium was used as a non-isotopic carrier of99Tc. On the basis of 3σ counting error, the detection limits were 4.9·10?5 Bq/l, 7.4·10?3 Bq/kg wet and 7.4·10?2 Bq/kg dry for water, biota and soil samples, respectively. Sea water, seaweeds (brown algae) and soils were collected to evaluate the present levels of99Tc in Japan. The level of99Tc in sea water was ca. 1·10?4 Bq/l around Japan. Among the seaweeds (brown algae), Ishige okamurai showed the highest concentration of 5.8·10?2 Bq/kg wet tissue and the highest concentration factor of 583. The level of99Tc in the organic rich surface soil was ca. 1 Bq/kg dry soil in Fukuoka. 相似文献
16.
Željko Grahek Gorana Karanović Marijana Nodilo 《Journal of Radioanalytical and Nuclear Chemistry》2012,292(2):555-569
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. 相似文献
17.
J. Solecki 《Journal of Radioanalytical and Nuclear Chemistry》2007,274(1):27-38
Research data on concentration and transportation of 90Sr in cutivate soils and its migration in undisturbed from Łęczna-Włodawa Lake District are presented. 90Sr analysis was based on yttrium path. A special attention was paid to the precision in excluding of Th and U radioisotopes
and their daughters using solid-liquid extraction (on Dovex ionite), and Pb by PbI2 precipitation. The obtained results revealed various contamination of studied soils by 90Sr although its concentration did not exceed 10 Bq/kg in the most samples. The highest concentration was noticed in upper
20 cm layers in both types of soils. Vertical migration rate of 90Sr, calculated from compartment model, was below 1 cm/yr for the most researched soils. 相似文献
18.
L. Liong Wee Kwong J. J. La Rosa S. H. Lee P. P. Povinec 《Journal of Radioanalytical and Nuclear Chemistry》2001,248(3):751-755
Liquid scintillation spectrometry has become the most widespread method for quantitative analysis of low level -emitters in environmental samples. This technique has been applied in the measurements of 241Pu, 3H and 90Sr in seawater and sediment samples. 241Pu can be measured by direct analysis of an electrodeposited source using - discrimination or by extraction of electrodeposited plutonium into a liquid form compatible with scintillation cocktail. Sediment from Mururoa and Fangataufa atolls showed activities ranging from 18 to 44 Bq/kg. A sediment profile sampled around Bikini Atoll in 1997 showed 241Pu activities ranging from 0.3 to 30 Bq/kg. 3H activities in pore water sediment from Mururoa and Fangataufa atolls were of the order of 103 Bq/m3 which demonstrated its underground origin. 90Sr was measured in the presence of 90Y. The counting efficiency was 92.41.5% and the background 0.027±0.001 s-1. The average chemical recovery for 90Sr was 673%. 相似文献
19.
N. Momoshima Y. Takashima M. Koike Y. Imaizumi T. Harada 《Journal of Radioanalytical and Nuclear Chemistry》1994,177(2):219-228
A determination procedure has been developed for210Bi and210Po in environmental samples and was applied for pine needles. Bismuth-210 and210Po separated from the parent nuclide210Pb as BiOCl precipitate were extracted simultaneously by TOPO/toluene containing PPO and POPOP. The separation of210Bi and210Po from210Pb was almost satisfactory. The activity of210Bi+210Po in the TOPO/toluene was measured periodically by liquid scintillation counting for about 20 days after separation. The time course of the decreasing pattern of the activity was determined by the initial activity ratio210Po/210Bi. The decreasing pattern of the activity was compared with theoretical patterns, and best estimates for210Po and210Bi were obtained by non-linear least-squares fitting. The activities of210Bi and210Po were determined for one-year and two-year old pine needles fro the same pine tree, and weathering half-time and deposition rate of these nuclides was discussed. 相似文献
20.
Separations of tracer cations in parent daughter systems such as carrier-free210Bi from210Pb,90Y from90Sr and UX1 from U have been carried out in a column of ceric phosphate as ion exchanger. The exchanger has been prepared by mixing ceric sulfate in hot 10M orthophosphoric acid at 80°C and keeping for overnight. A pale yellow coloured precipitate was formed which was washed, dried at 70°C for 48 hours when a hard, granular variety suitable for column use, with a cerium to phosphate ratio of 1∶2 was obtained. 0.1M H3PO4 was used as medium in each of the systems studied. The β-decay curves of the separated210Bi and90Y and the γ-spectrum of UX1 show that all these activities are radiochemically pure. The separation procedures adopted in each case were very clean and simple, gave quantitative yields and took less than half an hour. 相似文献