Determination of239,240Pu and241Am in environmental samples

An accurate and reliable method has been developed and routinely carried out for the sequential determination of^239,240Pu and²⁴¹Am in environmental samples. After suitable pretreatment.^239,240Pu and²⁴¹Am are separated from other elements by means of the anion exchange resin method. Americium-241 is purified by coprecipitation with calcium oxalate and then ion exchanged in mixed media of the mineral acid-methanol. In the analysis,²⁴²Pu (or²³⁶Pu) and²⁴⁴Cm are used as chemical yield monitors. The recoveries of the yield monitors in the analyses of some kinds of environmental samples were 7080% for plutonium and 7686% for curium. The concentration of^239,240Pu in the coastal sea water were 7.022 Bq/l and that of²⁴¹Am was 1.26.3 Bq/l. The mean concentrations of^239,240Pu in the edible parts of the marine products ranged from 0.22 to 7.4 mBq/kg · fresh and those of²⁴¹Am ranged from 0.11 to 2.6 mBq/kg · fresh.     

Determination of plutonium and americium in moss and lichen samples

A simple, sensitive and selective method is described for the simultaneous determination of plutonium and americium in lichen and moss samples which can be used as the atmospheric radioactivity bioindicators. Plutonium is separated from a HCl leaching solution by a Microthene-TNOA column; americium is separated by a KL-HDEHP column and purified by PMBP-TOPO extraction. A special attention has been paid to the decontamination of plutonium and americium from²¹⁰Po. Ten lichen and 12 moss samples from tree trunks have been analyzed: starting from 2 g sample, the average yields and the detection limits were 70.2±12.5% and 28 mBq/kg for plutonium and 70.0±15.1% and 34 mBq/kg for americium. The concentrations (mBq/kg) ranged from 28 to 4960 for^239,240Pu, from 28 to 171 for²³⁸Pu and from 34 to 1930 for²⁴¹Am, respectively.     

Die Bestimmung von Uran und Plutonium im Rahmen der Ausscheidungsanalyse

Zusammenfassung Eine in der Praxis angewandte Analysenmethode zur Bestimmung von Plutonium in Harnproben wurde mit Hilfe von Tracerversuchen mit²³⁶Pu,²³³U und²⁴¹Am hinsichtlich ihrer radiochemischen Ausbeute und ihrer Trenneffizienz überprüft. Dabei zeigte sich, daß die Pu-Bestimmung mit einer Ausbeute von 95% praktisch quantitativ erfolgt. Im allgemeinen ist es nicht notwendig, vom Restgehalt an Uran, der 25% beträgt, weiter abzutrennen. Bei Uranmengen bis zu 100g U (nat.) sind die Meßproben alphaspektrometrisch zur qualitativen und zur quantitativen Auswertung geeignet. Auf diese Weise kann neben der Pu-Bestimmung aus demselben Alphaspektrum einer Harnprobe auch eine Aussage über die Isotopenzusammensetzung des Urangehaltes und eine mengenmäßige Abschätzung getroffen werden.Die Abtrennung des²⁴¹Am erfolgt dagegen vollständig. Der Restgehalt an²⁴¹Am in der durch Elektrodeposition hergestellten Pu-Meßprobe wurde mit weniger als 0,3% ermittelt und ermöglicht eine Auswertung des Alphaspektrums auch auf²³⁸Pu.Die Ergebnisse von Routinemessungen im Rahmen der Personenüberwachung zeigten einen normalen Urangehalt im Harn von <0,3g U/l und einen normalen Plutoniumgehalt von 0,05 pCi²³⁹Pu/24 h-Harn.

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The determination of uranium and flutonium in excretion analysis

Summary A routine method for the determination of Pu in urine samples was tested with tracer amounts of²³⁶Pu,²³³U and²⁴¹Am for its recovery and for efficiency of radiochemical separation. Pu recovery was 95%, uranium about 25%, which in generally does not need to be separated for-spectrometric determination of Pu. With uranium content up to 100g U_(nat.) counting sources are suitable for qualitative and quantitative evaluation of-spectra. In this way additionally information about the isotopic composition and the amount of uranium in the urine sample can be achieved from the same measurement.Separation from²⁴¹Am, however, can be assumed quantitatively. The activity of²⁴¹Am in such counting sources prepared by electrodeposition was less than 0,3% which enables evaluation of²³⁸Pu too. Results of routine determinations in personnel monitoring show normal background levels of uranium concentration in urine samples of less than 0,3g U (nat.)/l and for plutonium of 0,05 pCi²³⁹Pu/24-hr urine samples.

     

Actinides in the near release from the Chernobyl NPP accident

Actinide elements concentrations in the products of near release from CNPP accident were estimated. The data on uranium,²³⁷Np,²⁴¹Am and plutonium and curium isotopes content in fuel particles are given. Sums of -emitting radionuclides and plutonium isotopes in reactor graphite particles and of uranium,²⁴²Cm,^239+240Pu isotopes in the soil and aerosol samples were also determined. By 1989 soil and dust contamination in near release of the accident is due to long-lived -emitting plutonium isotopes.     

Field performance test of PASS,an instrument for the rapid assay of plutonium and other γ-ray emitting radionuclides

A field performance test was conducted at the INEL with the mobile Rapid Transuranic Monitoring Laboratory (RTML) that was developed for the analysis of samples from sites or facilities potentially contaminated with plutonium, other actinides, and -ray emitting activation and fission-product radionuclides. The performance test and results are described for the Photon Analysis Spectrometer System (PASS), one of three RTML assay systems. This system consists of a thin-window, n-type Ge spectrometer, that automatically analyzes soil, smear, and air particulate-filter samples for actinides emitting L x rays, and for activation and fission products that emit rays. The measurements were blind and performed with 11-g soil samples gathered from the Cold Test Pit and with spiked samples containing known mixtures of²³⁹Pu,²⁴¹Am⁶⁰Co, and¹³⁷Cs. In the spiked samples the plutonium activity concentrations ranged from 75 to 500 pCi/g while the other radionuclides ranged from 10 to 130 pCi/g. Lower limits of detection (LLDs) were verified to be 1, 5, 5, and 40 pCi/g for²⁴¹Am,⁶⁰Co,¹³⁷Cs, and²³⁹Pu, respectively. Results from the performance test are presented.     

Determination of neptunium in plutonium and mixed uranium-plutonium samples by isotope dilution gamma-spectrometry with243Am as a spike

A method was developed for isolating neptunium from Pu, U or mixed oxide (MOX) samples and its determination by isotope dilution -spectrometry (IDGS) using²³⁹Np (²⁴³Am) as a spike. Extraction chromatography with trilaurylamine fixed on a SGX-C18 support was used for the isolation of Np. The decontamination factors for U, Pu, Am and Pa vary between 1000–2000 and 100, respectively. The average separation yield of Np is (95±3)%. The amount of²⁴³Am required for spiking is about 0.2–0.3 g. It is recommended to use the pair of -rays 86.53 keV (²³⁷Np)-106.13 keV (²³⁹Np) for the assay of neptunium. A relative uncertainty of 4% or better is achievable in the analysis of plutonium samples, containing 0.4–80 g neptunium. The detection limit, under the proposed experimental conditions, is about 0.05 g Np. The results were compared with the results obtained by using high resolution -spectrometry (HRGS).     

Plutonium and americium in sediment samples along the Romanian sector of the Danube river and the Black Sea coast

The concentrations of²³⁸Pu,^239,240Pu and²⁴¹Am were determined in eight sediment samples, collected from the bed of the Romanian sector of the Danube river and the Black Sea coast during 1994 and 1995. Fusion with potassium carbonate was used to achieve complete dissolution of the samples. Tracers,²⁴²Pu and²⁴³Am, were added and the separation of plutonium from americium, uranium and thorium was performed by anion exchange. Americium was separated from uranium in two steps, using a conventional anion exchange resin and an extraction chromatographic resin for transuranics. After electrodeposition on stainless steel discs the nuclides were counted with -spectrometry with -PIPS detectors. The total plutonium concentrations obtained by this method were compared with the acid leachable plutonium concentrations reported for the same samples in a previous paper.     

Production of96Tc and95mTc via the93Nb(α, xn) Reactions

Relatively longer liver technetium tracers such as^95mTc (61 d) are useful for the development, evaluation and comparison of new technetium complexes for eventual development of^99mTc radiopharmaceuticals. The feasibility of producing⁹⁶Tc (4.35 d) and^95mTc (61 d) was studied by the alpha bombardment of pure Nb targets (⁹³Nb-100%).⁹⁶Tc was obtained in a yield of 30 Ci/Ah using 16 MeV alphas, but it contained significant activity of⁹⁵Tc (20 h) Relatively pure⁹⁶Tc and^95mTc was produced in yields of 18 Ci/Ah and about 1 Ci/Ah respectively with alphas of suitable energy and after allowing for suitable cooling periods after the end of bombardment (EOB).     

Nuclear interferences of uranium and thorium in a reactor neutron activation analysis determination of cerium using the radionuclides141Ce and143Ce

The interference contributions of uranium and thorium to the determination of cerium based on radionuclides¹⁴¹Ce and¹⁴³Ce produced by irradiation in a reactor core was determined. The values of the interference contributions for¹⁴¹Ce were 0.28±0.01 g Ce/g U and /2.01±0.05/x10^–3 g Ce/g Th, and for¹⁴³Ce 1.33±0.03 g Ce/g U and /9.0±0.2/x10^–3 g Ce/g Th.     

Synthesis,characterization and x-ray structure of V3(μ3-O)(μ-Cl)Cl6(μ-η1-η1-PhNHNH2)2(PhNHNH2)2(THF) · 6THF: A new binding mode for phenylhydrazine

Addition of phenylhydrazine to a mixture of VCl₃ · THF/N,N-propyl-bis (salicyladimine) and sodium hydride yielded a trinuclear vanadium complex, V₃(₃-O)(-Cl)Cl₆(-¹-¹PhNHNH₂)₂(PhNHN H₂)₂(THF), containing two bridging and two terminal phenylhydrazine ligands. The product has been crystallographically characterized (P2₁/n, a=12.949(2) Å,b=24.061(4) Å,c=22.504(4) Å, =107.22(1) deg.,V=6697(2) ų withZ=4) and was found to contain the first example of bridging monosubstituted hydrazine (phenylhydrazine) ligands.     

Ion-exchange separation of uranium,thorium and plutonium isotopes from environmental samples

Radioisotopes of uranium, thorium and plutonium in water, soil and fertilizer samples, have been chemically separated and determined by alpha-spectrometry method. Radiochemical procedure involving ion-exchange, enabled to determine these isotopes in very low concentrations (under 50 Bq/g).²³²U,²²⁹Th and²³⁸Pu were used as a tracers for radiochemical yield recoveries (up to 90%). Thin layer sources have been obtained by electrodeposition.     

Precise coulometric determination of uranium,plutonium and americium-application to small samples

Summary Isotopic dilution followed by mass spectrometry is currently used for the determination of microquantities of actinides, but for this method it is necessary to prepare certified solutions of isotopic diluents. The isotopes used are very expensive and often available only in small quantities. New methods have been developed for the accurate and precise determination of small amounts of uranium, plutonium and americium. By using controlled-potential coulometry 0.5eq of uranium and plutonium can be determined with a precision of 0.1% (coefficient of variation). For americium a constant-current coulometric titration allows the determination of 1eq with a precision of 0.3%. The equipment, coulometric cells and procedures are described. The results obtained for standard materials and comparisons with results from other analytical methods are given.

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Genaue coulometrische Bestimmung von Uran, Plutonium and Americium; Anwendung auf kleine Proben

Zusammenfassung Isotopenverdünnung und nachfolgende Massenspektrometrie werden laufend für die Bestimmung kleiner Mengen von Actiniden verwendet; dazu ist es aber notwendig, genaue Lösungen von Isotopen zur Verdünnung herzustellen. Die dazu verwendeten Isotopen sind sehr teuer und oft nur in sehr kleinen Mengen zu haben. Für die genaue Bestimmung kleiner Mengen Uran, Plutonium und Americium wurden neue Methoden ausgearbeitet. Unter Verwendung der potential-kontrollierten Coulometrie lassen sich 0,5eq Uran und Plutonium mit einer Genauigkeit von 0,1% (Variations-Koeffizient) bestimmen. Gleichstromcoulometrische Titration ermöglicht die Bestimmung von 1eq Americium mit einer Genauigkeit von 0,3%. Einrichtung samt coulometrischer Zellen und Arbeitsweise wurden beschrieben. Die mit Standardproben erzielten Resultate wurden mit den Ergebnissen anderer Verfahren verglichen.

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Presented at the 8th International Microchemical Symposium, Graz, August 25–30, 1980.     

Research for technique of preparing high-intensity241Am low-energy gamma-source

Systematically complicated technique used for preparing high-intensity (more than 8.0 GBq/cm²)²⁴¹Am -source by a new enamel technique is presented. High intensity²⁴¹Am -sources with activities ranging from 3.7 to 37 GBq have been made by this new technique. The activity and photon output have been measured. The results were compared with the data reported by the Radiochemical Centre Amersham in their specification. The photon output of²⁴¹Am -source produced by us meets the technical specification of²⁴¹Am -sources produced by Amersham. Moreover, the highest intensity can reach 1789 mCi/cm². The overall utilization ratio of²⁴¹Am activity (59.5 keV) is 31.2%.     

Elemental characterization of airborne particulates at two Nigerian locations during the Harmattan season

Airborne particulate matter collected during the Harmattan season at Kano in the northern part, and Ile-Ife in the southern part of Nigeria was analyzed for about 30 elements by a combination of instrumental neutron activation analysis and X-ray fluorescence analysis. Although the total suspended particulate concentration (ng/m³) is much higher in Kano than Ife, the elemental composition at both locations is very similar and cluster analysis shows a strong correlation between the two, indicating a common origin for particulates. Particle-size distribution studies show that Kano dust is mainly coarse while Ife dust is mainly fine. The crustal-type elements are mainly concentrated in the coarse particles (3 m) at both locations while the conventional anthropogenic elements are hosted mainly by the fine particles (0.49 m and below).     

Procedures to define Pu isotopic ratios characterizing a contaminated area in Palomares (Spain)

Plutonium isotopic ratios have been calculated in soils contaminated by the Palomares accident which occurred in 1966 (Almería, Southeastem Spain). Contrasted techniques have been used to determine the radionuclide activities:²³⁸Pu and^238+240Pu were analysed by -spectrometry prior purification on anion-exchange resins, the ratio²³⁹Pu/²⁴⁰Pu was estimated by -spectra deconvolution and²⁴¹Pu was directly measured by liquid scintillation counting and indirectly through quantification of in-grown²⁴¹Am from aged plutonium discs. The mean activity ratios²³⁸Pu/²³⁹Pu,²³⁹Pu/²⁴⁰Pu,²⁴¹Pu/²³⁹Pu, backdated to 1966, were 0.027±0.002 (1), 4.5±0.2 (1) and 8.2±0.8 (1), respectively, characterizing the accident of Palomares as the source term of the measured plutonium.     

Application of l-cysteine-capped nano-ZnS as a fluorescence probe for the determination of proteins

Nanometer-sized l-cysteine-capped ZnS particles have been synthesized and used as a fluorescence probe to investigate the effect of proteins on fluorescent intensity. With =190 nm, maximum and constant synchronous fluorescence enhancement was produced at 267 nm and pH 5.12 in the presence of proteins. A highly sensitive synchronous fluorescence method for the rapid determination of proteins has been developed. Under optimum conditions, calibration graphs are linear over the range 0.03–8.0 g mL^–1 for bovine serum albumin (BSA), 0.01–6.0 g mL^–1 for human serum albumin (HSA), 0.05–8.0 g mL^–1 for -globulin (-G), and 0.04–4.0 g mL^–1 for ovalbumin, respectively. The relative standard deviations of seven replicate measurements were 1.75% for 1.0 g mL^–1 BSA, 1.90% for 1.0 g mL^–1 HSA, 1.65% for 1.0 g mL^–1 -G, and 2.32% for 1.0 g mL^–1 ovalbumin.     

Determination of pyrimethanil and kresoxim-methyl in soils by headspace solid-phase microextraction and gas chromatography-mass spectrometry

A method using headspace solid-phase microextraction (HS-SPME) then gas chromatography–mass spectrometry with selected ion monitoring (GC–MS, SIM) has been developed for determination of trace amounts of the fungicides pyrimethanil and kresoxim-methyl in soil and humic materials. Both fungicides were extracted on to a fused-silica fibre coated with 85 m polyacrylate (PA). Response-surface methodology was used to optimise the experimental conditions. For soil samples the linear dynamic range of application was 0.004–1.000 g g^–1 for pyrimethanil and 0.013–1.000 g g^–1 for kresoxim-methyl. The detection limits were 0.001 g g^–1 and 0.004 g g^–1 for pyrimethanil and kresoxim-methyl, respectively. HP-SPME–GC–MS analysis was highly reproducible—relative standard deviations (RSD) were between 6.7 and 12.2%. The method was validated by analysis of spiked matrix samples and used to investigate the presence of pyrimethanil and kresoxim-methyl above the detection limits in soil and humic materials.     

Effects of Fe(III) ions on the electrodeposition of trace amounts of plutonium and americium

The electrodeposition of Pu and Am onto stainless steel discs from 3.2M ammonium chloride solution is strongly affected by the iron concentration of the electrolyte. At Fe(III) concentrations of more than 0.1mM (30 g Fe in 5 ml) only 30–40% of²³⁶Pu and 6% of²⁴¹Am can be deposited. Tracer experiments with⁵⁹Fe suggest that exchange processes take place between Fe from the surface layer of the cathode and from the electrolyte. Double tracer studies show increasing²³⁶Pu/⁵⁹Fe- and decreasing²⁴¹Am/⁵⁹Fe-ratios with increasing iron content of the electrolyte, which may be due to different sorption properties on colloidal iron hydroxides formed at pH<3.6.     

Elements in car and truck tires and their volatilization upon incineration

The trace metal loading of used car and truck tires and the fractions of the metals volatilized upon incineration of the tire were determined. INAA was chosen due to its multielement analysis capability and its low detection limit for many elements. A high purity planar germanium detector was used. Among the elements measured were, Al (4–150 g/g), Ti (41–730 g/g), V (0.04–0.4g/g), Mg (>80–580 g/g), Zn (1–2.2%) as typical concentrations; also some amounts of antimony, bromine and arsenic have been found. Major differences in elemental concentrations have been observed between the tread and the wall of a tire, and also between different brands.     

New cobalt trimethylacetate complexes with pyridine

The reaction of the tetranuclear trimethylacetate complex Co₄(₃-OH)₂(-OOCCMe₃)₄(²-OOCCMe₃)₂(EtOH)₆ with pyridine in acetonitrile was studied. Two new compounds, viz., the hexanuclear cobalt(ii) complex Co₆py₄(₃-OH)₂(-OOCCMe₃)₁₀ (25% yield) and the unusual ionic compound [Co₃py₃(₃-O)(-OOCCMe₃)₆]⁺[Co₄py(₄-O)(-OOCCMe₃)₇]^– (5% yield), were prepared. The structures of the new compounds were established by X-ray diffraction analysis.