Radioanalytical Methods Research Articles

Laudation for Professor Susanta Lahiri Hevesy Medal Awardee 2015

Susanta Lahiri was born in Darjeeling, India, in 1961. He received his PhD (1994) from the University of Calcutta. In the same year he started his career as a lecturer (Assistant Professor) in Chemistry at the University of Burdwan, India. He moved to the Saha Institute of Nuclear Physics in 1997 where he became a Professor in 2003 and a Senior Professor in 2013. He is also a Professor at Homi Bhabha National Institute, Bhabha Atomic Research Centre in Mumbai, India. Professor Lahiri’s work is associated with many ‘‘firsts’’. In his early career, he started cyclotron production of no-carrier-added (NCA) radionuclides by alpha particle activation. Prof. Lahiri was the first scientist to irradiate lanthanide targets by heavier projectiles like Li, B, C, O etc. which made access to neutron deficient short-lived radioisotopes easier and expanded the horizon of clinically important radionuclides. He introduced the ‘‘tracer packet’’ idea, which allows one to deal with many similar radioactive tracers at-a-time in one experiment rather than setting up many experiments with individual tracers. His group is developing a number of green chemistry radioanalytical methods based on aqueous biphasic systems and room temperature ionic liquids. His group reported the first green chemistry synthesis of radioactive gold nanoparticles by adding HAuCl4 to polyethylene glycol. Professor Lahiri and his colleagues also joined the TASCA group in GSI, Germany. Recently they independently confirmed E-117. Neutrino mass measurement is a burning problem of fundamental science. Professor Lahiri’s team, for the first time, proposed indirect production route of Ho via Dy/Er and Tb/Er reactions to increase the yield of Ho by orders of magnitude to help neutrino studies. He carried out most of his basic Nuclear Chemistry work using medium energy accelerators in Mumbai and Kolkata and complemented it by collaborating with international institutions such as CERN, GSI, Heidelberg University, Institute of Modern Physics in China, TU Munich, ATOMKI Hungary, TU Delft, ETH Switzerland, and others. His team for the first time unveiled the total radionuclide inventory produced by bombardment of 1.4 GeV proton on thick lead–bismuth target. In a nutshell, Prof. Lahiri’s wide research interest is reflected in about 190 publications in international journals, and 250 reports in international and national conferences. He made contributions in ten books. He has received several national and international awards. He is a member of distinguished reviewers’ board of JRNC since 2005. He has supervised 11 PhD and 26 MSc theses so far. In recognition of his contribution in Nuclear Chemistry, The University of Calcutta conferred the highest academic honor, namely DSc degree, upon him in 2009. The title of his DSc dissertation was ‘‘Production and separation of carrier free radionuclides’’. Recently Indian Chemical Society bestowed him ‘‘Acharya J. C Ghosh Memorial Award’’ for the year 2014. It is indeed a pleasure to honor Prof. Susanta Lahiri with the Hevesy Medal Award 2015 for his outstanding contributions on heavy ion induced radioisotope production, tracer packet technique, converter targets, and green chemistry. The Hevesy Medal Award Selection Panel 2015 (HMASP-15) consisted of Professor Amares Chatt (Dalhousie University, Canada; also Chair of JRNC Board of & A. Chatt chatt@dal.ca

Compositional characterization of lithium titanate ceramic samples by determining Li, Ti and O concentrations simultaneously using PIGE at 8 MeV proton beam

Lithium titanate is a proposed tritium breeding blanket material in D-T based fusion reactor under International Thermonuclear Experimental Reactor programme. For optimization of sol–gel preparation method and chemical quality control, compositional characterization of Li2TiO3 was carried out by particle induced gamma-ray emission using 8 MeV proton beam at BARC–TIFR pelletron facility. For the first time, a non-destructive method has been standardized for simultaneous determination of Li, Ti and O in this ceramic sample, which is otherwise difficult by various wet-chemical as well as radio-analytical methods. Thick targets of samples, synthetic samples and standards prepared in graphite matrix were used for the experiment. Rutherford backscattering spectrometry method was used for beam current monitoring using a thin Au foil. The gamma-rays at 478, 983 and 6129 keV from 7Li(p, p′γ)7Li, 48Ti(p, p′γ)48Ti and 16O(p, p′γ)16O nuclear reactions, respectively, were measured using high resolution gamma-ray spectrometry and corresponding peak areas were used for concentration calculations by relative method.

Porous chromatographic materials as substrates for preparing synthetic nuclear explosion debris particles

Several porous chromatographic materials were investigated as synthetic substrates for preparing surrogate nuclear explosion debris particles. Eighteen metals, including some of forensic interest, were loaded onto materials by immersing them in metal solutions (556 mg/L of each metal) to fill the pores, applying gentle heat (110 °C) to drive off water, and then treating them at high temperatures (up to 800 °C) in air to form less soluble metal species. High-boiling-point metals were uniformly loaded on spherical controlled-pore glass to emulate early fallout, whereas low-boiling-point metals were loaded on core–shell silica to represent coated particles formed later in the nuclear fallout-formation process. Analytical studies characterized material balance and the formation of recalcitrant species. Metal loading was 1.5–3 times higher than expected from the pore volume alone, a result attributed to surface coating. Most metals were passively loaded; that is, solutions filled the pores without active metal discrimination. However, niobium and tin concentrations were lower in solutions after pore filling, and were found in elevated concentrations in the final products, indicating selective loading. High-temperature treatments caused reduced solubility of several metals, and the loss of some volatile species (rhenium and tellurium). Sample preparation reproducibility was high (the inter- and intra-batch relative standard deviations were 7.8 and 0.84 %, respectively) indicating suitability for use as a working standard for analytical methods development. We anticipate future standardized radionuclide-loaded materials will find use in radioanalytical methods development and/or serve as a starting material for the synthesis of more complex nuclear explosion debris forms (e.g., Trinitite).

Evaluation of trace elemental composition of aerosols in the atmosphere of Rawalpindi and Islamabad using radio analytical methods

Geological and anthropogenic contributions to air pollution were monitored by analyzing aerosol particulates present in the atmosphere of Rawalpindi and Islamabad, Pakistan, using instrumental neutron activation for trace elemental analysis. A scanning electron microscope was used to study particulate size distribution and morphology. Twenty two elements were analyzed and their likely sources were identified. It was found that 69% of the suspended particulate matter in the atmosphere of Islamabad, and 52% in Rawalpindi, were of a diameter less than 3μm. The presence of Yb, Cs, Sc, Rb, Co, Eu, La, Ba, Zn and Hf indicates that a major portion of the trace elements in the aerosol particulates was due to the geological nature of the land, while Sc was considered to be arising from coal burning. The presence of Cr, Fe, Ce, Pb and Cd was attributed to anthropogenic activities at Rawalpindi and Islamabad. Unusually high concentrations of Mo and Nb were found in the atmosphere of Islamabad, based on soil derived aerosols.

Analytical methods to determine 210Po and 210Pb in marine samples

This paper describes the methods of sampling, preconcentration, chemical separation and final count of 210Po and 210Pb present in different marine matrices to determine their background levels in a marine ecosystem. Complex, time consuming and selective radioanalytical methods have been used to prepare final clear sources for alpha spectrometry and beta count; in fact, gamma spectrometry, a method direct and non destructive, cannot be taken into account because the 210Pb activity is very low which does not allow to carry out sufficiently accurate measurements and 210Po is not a gamma emitter but it emits only alpha particle at 5.40MeV. The results of 210Po and 210Pb activity concentrations obtained in different marine samples collected in the first two campaigns are still very few to discuss about the 210Po and 210Pb behavior in marine environment.

Assessment of labelled products with different radioanalytical methods: study on 18F-fluorination reaction of 4-[18F]fluoro-N-[2-[1-(2-methoxyphenyl)-1-piperazinyl]ethyl-N-2-pyridinyl-benzamide (p-[18F]MPPF)

The serotonin receptor 5-HT1A ligand 4-[18F]fluoro-N-[2-[1-(2-methoxyphenyl)-1-piperazinyl]ethyl-N-2-pyridinyl-benzamide (p-[18F]MPPF) was produced by a simplified method of Le Bars et al. Traditional oil bath heating was compared to microwave heating. Various radioanalytical methods, radio-Thin Layer Chromatography (TLC), High Pressure Liquid Chromatography (HPLC) and Mass Spectrometry (MS), were compared in the evaluation of the labelled product(s). The crude reaction mixture consisted of p-[18F]MPPF and 2–4 radioactive by-products eluting after the product fraction, and the reverse-phase HPLC method failed occasionally to separate p-[18F]MPPF from the radioactive by-product with close retention time. The heating method had no significant effect on the composition of labelled by-products. In LC-(ESI)-MS analysis of p-[18F]MPPF the labelled product was identified with m/z ratio of 435 ([M + H+]). The other HPLC fractions were measured to have following m/z ratios: (1) 327; 349; (675) (2) 402; 407/408; (791) and (3) 436, suggesting different kind of decomposition of the labelled product and/or the inactive precursor. The ion trap mass spectrometer was sufficient for the qualitative analysis of p-[18F]MPPF. However, differentiation of by-products arising from the decomposition of p-[18F]MPPF or from its precursor p-MPPNO2 proved to be challenging.

ChemInform Abstract: Radiometric Determination of Trace Elements

Many radioanalytical methods have been introduced for trace analysis. Each method has its own advantages, but in comparison with ordinary instrumental nuclear methods, these radioanalytical methods, except for substoichiometry, have not been applied to analysis of many actual samples. Substoichiometric analytical methods including substoichiometric radioactivation analysis will come to be more widely used, as a result of the many possible applications.

Rapid radiochemical sample preparation for alpha spectrometry using polymer ligand films

Rapid radioanalytical methods are adversely affected by many different sample-matrix interferences, which make analyzing samples a difficult and time consuming process. A new method for preparing radioactive samples for analysis by alpha spectrometry has been demonstrated. In this technique, a selective extractive ligand is immobilized in a polymer film coated on a metal surface. This polymer ligand film is then used to extract plutonium and other radioactive analytes from solution over a short period of time. The prepared substrate is then counted directly by alpha spectroscopy in a small single detector alpha spectrometer. The method has been demonstrated for the analysis of americium and plutonium in liquid samples such as water and urine.

PHYSICOCHEMICAL CHARACTERIZATION OF CAPSTONE DEPLETED URANIUM AEROSOLS I: URANIUM CONCENTRATION IN AEROSOLS AS A FUNCTION OF TIME AND PARTICLE SIZE

During the Capstone Depleted Uranium (DU) Aerosol Study, aerosols containing DU were produced inside unventilated armored vehicles (i.e., Abrams tanks and Bradley Fighting Vehicles) by perforation with large-caliber DU penetrators. These aerosols were collected and characterized, and the data were subsequently used to assess human health risks to personnel exposed to DU aerosols. The DU content of each aerosol sample was first quantified by radioanalytical methods, and selected samples, primarily those from the cyclone separator grit chambers, were analyzed radiochemically. Deposition occurred inside the vehicles as particles settled on interior surfaces. Settling rates of uranium from the aerosols were evaluated using filter cassette samples that collected aerosol as total mass over eight sequential time intervals. A moving filter was used to collect aerosol samples over time, particularly within the first minute after a shot. The results demonstrate that the peak uranium concentration in the aerosol occurred in the first 10 s after perforation, and the concentration decreased in the Abrams tank shots to about 50% within 1 min and to less than 2% after 30 min. The initial and maximum uranium concentrations were lower in the Bradley vehicle than those observed in the Abrams tank, and the concentration levels decreased more slowly. Uranium mass concentrations in the aerosols as a function of particle size were evaluated using samples collected in a cyclone sampler, which collected aerosol continuously for 2 h after perforation. The percentages of uranium mass in the cyclone separator stages ranged from 38 to 72% for the Abrams tank with conventional armor. In most cases, it varied with particle size, typically with less uranium associated with the smaller particle sizes. Neither the Abrams tank with DU armor nor the Bradley vehicle results were specifically correlated with particle size and can best be represented by their average uranium mass concentrations of 65 and 24%, respectively.

Vertical distribution of 226Ra and 210Po in agricultural soils in Buyuk Menderes Basin, Turkey

The vertical distribution of 226Ra and 210Po was investigated in the cultivated soils of the Buyuk Menderes Basin in Turkey. Five soil cores down to a depth of about 50 cm were taken from each site and divided into strata of 2–3 cm intervals. The samples were analyzed for their 226Ra and 210Po activity concentrations using radioanalytical methods. Down-core concentration profiles of 226Ra and 210Po in the soil cores from five sites are obtained. The activity concentrations of soil cores range from 80 to 1170 Bq kg −1 for 226Ra and from 10 to 870 Bq kg −1 for 210Po with the depth. Analysis of the vertical soil profiles indicate that the activity concentrations of 226Ra and 210Po for soil strata at all the sites have not extremely changed with depth.

Measurement of low levels of radioactivity with a large well germanium detector

Described is the application of a state-of-the-art germanium detector containing a 25.4-mm diameter by 50-mm deep well for low-level activity gamma-spectrometry measurements. Detector calibration with examples of absolute efficiency curves at different in-well sample heights and the results of experiments to determine the effect of sample matrices to gamma-ray adsorption are presented. Radioanalytical methods described include the measurements of 241,243Am: (1) in water samples after preconcentration and (2) in dissolved neodymium fluoride (NdF3) microprecipitates. These procedures were achievable because of the well detector’s ability to accommodate a relatively large sample volume. A rapid method for the dissolution of NdF3 microprecipitates for gamma counting is also described.

An inductively coupled plasma mass spectrometry method for the quantification of yttrium‐antibody based drugs using stable isotope tracing

Targeted radioimmunotherapy has been recently clinically validated and approved for the treatment of cancer by the US Food and Drug Administration. This therapeutic approach employs monoclonal antibodies directed to cancer-related, cell-surface antigens coupled to beta-emitting nuclides. 90Y is one of the most useful radioisotopes in the development of antibody based radioimmunotherapy and evaluation of the pharmacokinetic profile for 90Y-radiopharmaceuticals is usually performed by radiochemical methods. In this work we have developed an alternative radioactive-free approach to evaluate pharmacokinetic profiles based on the inductively coupled plasma mass spectrometric (ICP-MS) quantification of 89Y. A highly sensitive and rapid method for the determination of yttrium in urine is described and applied to evaluate the urinary clearance of antibody-based drugs labeled with the stable isotope of yttrium, 89Y. This approach overcomes some important limitations for pre-clinical radioanalytical methods such as radiation hazards and radioactive waste disposal. Method development was performed by determining detection and quantification limits, and precision as repeatability and trueness. These performance parameters fulfilled the acceptance criteria for bioanalytical methods.

Determination of plutonium and 90Sr in air particulate samples

Within the surveillance program of the gaseous effluents coming from the nuclear reprocessing plant EUREX of ENEA (Italian National Agency for New Technologies Energy and Environment, CR Saluggia) in the North of Italy, the content of some radionuclides is continuously monitored. The so-called 1AW high-activity liquid waste (HLLW) is the aqueous raffinate of the first cycle of PUREX extraction process which was the starting point of the reprocessing activity of some MTR and CANDU spent fuel elements. Nowadays, 1AW-HLLW is stored in five tanks placed inside the EUREX plant site. This paper describes the sampling and radioanalytical methods employed to determine the activities of 241Am, plutonium isotopes and 90Sr in the total suspended particulate material (TSP) of the 1AW tank primary ventilation air circuit.

Quality assessment of hydrosphere in the vicinity of Czech nuclear power plants by radioanalytical methods

The paper deals with the impact of nuclear plants and radioactive waste disposal on surface and ground water quality in their vicinity using various radiometric and radioanalytical methods. The impact of nuclear power plant Temelin on activation concentrations and fission products in hydrosphere, including tritium, was detected. The annual average tritium concentrations in Vltava River correspond to the previously calculated estimates for average and minimal quaranteed flow rates. The concentrations histories of 90Sr and 137Cs in surface water show a decreasing trend. This trend was not influenced by the nuclear power plant pilot operation. In the case of tritium, a concentration increase trend has been already observed since the startup of pilot operation. An attempt has made interpreting the sorption and diffusion data for radionuclides of cesium, strontium and tritium and technetium as representatives of multivalent elements. Sorption and diffusion data of 137Cs and 90Sr in contact with natural sorbent bentonite lead to the conclusion that both diffusion and batch sorption experiments can be simulated by an exchange model. Sorption of technetium on various bentonites plus additives materials is described. Retention of technetium on these solid phases is driven by sorption of reduced form of technetium Tc(IV).

Development of a radioanalytical emergency procedures manual database (REPMD)

A Radioanalytical Emergency Procedures Manual Database (REPMD) will be an important tool to assist laboratories preparing for emergency response to a sudden release of radioactivity into the environment. The collection and systematic organization of existing sampling, screening and radioanalytical methods will enable laboratories to assess the appropriate methodologies for their use. REPMD is intended to be flexible, searchable, and interactive to accommodate a wide range of available techniques while being protected from unauthorized modifications. Website access by the world-wide scientific community will make the database a foundation for international comparison. The information in the database will also serve as a comprehensive and periodically updated source of methods and procedures suitable for training programs and rapid reference.

Identification of selenoproteins in the endoplasmatic reticulum of the rat kidney by combination of radioanalytical techniques and biochemical methods

Investigations have been carried out on rats to obtain information about the selenium-containing proteins present in the microsomal fraction and especially in the endoplasmatic reticulum (ER) of the kidney. For the determination of the selenium levels instrumental neutron activation analysis via 75Se was used. After labeling of rats in vivo with 75Se-selenite and separation of the proteins in the renal homogenate and cell compartments by electrophoretic methods, the 75Se-containing proteins were detected by autoradiography. In this way, six selenium-containing proteins with molecular masses of 15, 16, 20, 23-25, 40-42 and 58-60 were found in the endoplasmatic reticulum. All of those were characterized as selenocysteine-containing selenoproteins.

234Th distributions in coastal and open ocean waters by non-destructive β-counting

Non-destructive β-counting analyses of particulate and dissolved 234Th activities in seawater are simpler but no less precise than traditional radioanalytical methods. The inherent accuracy limitations of the non-destructive β-counting method, particularly in samples likely to be contaminated with anthropogenic nuclides, are alleviated by recounting the samples over several half-lives and fitting the counting data to the 234Th decay curve. Precision (including accuracy, estimated at an average of 3%) is better than 10% for particulate or 5% for dissolved samples. Thorium-234 distributions in the Skagerrak indicated a vigorous, presumably biological, particle export from the surface waters, and while bottom sediment resuspension was not an effective export mechanism, it did strip thorium from the dissolved phase. In the Greenland and Norwegian Seas, we saw clear evidence of particulate export from the surface waters, but at 75 m, total 234Th activities were generally in equilibrium with 238U.

High resolution γ-spectrometry by HPGe detector and β-spectrometry by liquid scintillation counting, hyphenated to elemental analysis techniques: applications of high specific activity radio-nuclides for ultra-trace metallo-toxicological and environmental studies

Thin- and thick-target excitation functions of 188,189,191Pt radionuclides were experimentally determined by cyclotron irradiation, using nuclear reactions natOs(α,xn) in the energy range up to 38 MeV with the Scanditronix-MC40 Cyclotron of the Joint Research Centre-Ispra, VA (Italy) of the European Communities. Radionuclidic, radiochemical and chemical purities have been also measured by use of analytical and radioanalytical techniques. In this paper, the result of the experimental thick- and thin-target excitation functions of 188,189,191Pt radiotracers, produced via natOs(α,xn) reactions, are presented. The data are of relevant interest for optimising cyclotron production of platinum radionuclides to be used as radiotracers for metallo-biochemical, biomedical, toxicological and environmental studies. In this paper, we will present the analytical and radioanalytical methods that have been developed to determine the amount of isotopic carrier and the SA(NCA) in the case of 188Pt, 191Pt, to be used for ‘multiple labelling’ experiments, by: high resolution γ-spectrometry, β-spectrometry by liquid scintillation counting, neutron activation analysis, FL-AAS, and ICP-OES. Moreover, some preliminary biological applications were carried out in order to determine the cyto-toxicology of different chemical forms of platinum.

226Ra in geothermal and bottled mineral waters of Hungary

Geothermal waters have been used on a large scale for bathing, drinking and medical purposes, while the consumption of bottled mineral waters is increasing. In this work, radon and radium activity concentrations of thermal and bottled mineral waters, originating from different regions of Hungary, were studied by different radioanalytical methods. It was found that the thermal springs, which supply the world famous baths of Budapest along the right riverside of the Danube, have high 222 Rn and 226 Ra activity concentration: up to about 100 and 1 kBq m −3 , respectively. The radium content of some investigated geothermal waters found in the NE region of the Great Hungarian Plain is even higher: up to several kBq m −3 . The 226 Ra content of bottled mineral waters, commercially available in Hungary, was determined by gamma-spectrometric method, applying radiochemical separation. The highest value exceeded 2 kBq m −3 in the case of the Apenta mineral water, which is a popular brand in Hungary, as well as in Europe and North America.

Diode-laser-based resonance ionization mass spectrometry of the long-lived radionuclide 41Ca with

There are a number of applications requiring measurement of the long-lived radionuclide 41 Ca at isotopic abundance, relative to 40 Ca, in the range of 10-8 to 10-16 . The long lifetime and electron-capture decay mode make radio-analytical measurements impractical and conventional mass spectrometric methods can not overcome isobaric interferences such as 41 K+ or 40 CaH+ at these levels. We approach this problem by combining laser-based resonance ionization spectroscopy with mass spectrometry. Using high-resolution single-mode lasers for resonant excitation and an intense non-resonant laser for ionization of the selectively created excited-state atoms, it is possible to essentially eliminate interference from isobars and to obtain additional optical isotopic selectivity, which can be combined with that of the mass spectrometer. Single-, double-, and triple-resonance excitation schemes have been investigated experimentally and theoretically, and it is found that performance with respect to both selectivity and sensitivity increases dramatically with each additional resonance step. Thus far, triple-resonance measurements have demonstrated minimum detectable isotopic abundance of 2.5·10-13 with detection limits of ~2·105 atoms.