A study of the extraction of plutonium from planchets by Aridus–ICP–SFMS

Two extraction processes of plutonium (Pu) on planchets from alpha spectrometry (AS) have been evaluated by inductively coupled plasma sector field mass spectrometry with a desolvator system (Aridus–ICP–SFMS). The samples were traced with known concentrations of ²³⁹Pu (1.2 × 10³ fg) and ²⁴²Pu (2 × 10³ fg) followed by an electrodeposition in planchets, according to the Hallstadius method. The processes of extraction were carried out with 50 mL of 0.36 mol L^?1 HNO₃ every 30 min up to 180 min in a glass beaker at 60 °C. The first process was on a hotplate and the second used an ultrasonic system. Finally, samples were evaporated to dryness, and resuspended in 10 mL of 0.72 mol L^?1 HNO₃ for evaluation. The results showed that at 120 min, a ~70 % recovery of ²³⁹Pu and a ~80 % recovery of ²⁴²Pu in both processes were obtained. The average recoveries of ²³⁹Pu and ²⁴²Pu at 180 min using the hotplate in plate were 93.4 ± 4.6 and 93.7 ± 4.2 % respectively, and with the ultrasonic system were 96.0 ± 4.3 and 98.2 ± 1.0 % respectively. In conclusion, both processes are suitable for Pu extraction, and Aridus–ICP–SFMS is an essential technique for the reassessments and quantification of Pu. In addition, procedural blanks spiked with 1 × 10² fg mL^?1 U were prepared for each process, in order to study the contribution of the ²³⁸U on the background signal at m/z = 239, which was 0.5 ± 0.2 cps, indicating that the contribution of ²³⁸U on the ²³⁹Pu signal was negligible. Furthermore, this methodology can be applied to sample planchets with environmental, food, biological and nuclear origin, and thereby to avoid repetitive analysis when Pu concentration determined by AS are under minimum detectable activities.     

Determination of trace amounts of plutonium in low-active liquid wastes from spent nuclear-fuel reprocessing plants by flow injection-based solid-phase extraction/electrochemical detection system

A flow injection-based electrochemical detection system coupled to a solid-phase extraction column was developed for the determination of trace amounts of plutonium in low-active liquid wastes from spent nuclear-fuel reprocessing plants. The oxidation state of plutonium in a sample solution was adjusted to Pu(VI) by the addition of silver(II) oxide. A sample solution was made up in 3 mol L^?1 HNO₃ and loaded onto a column packed with UTEVA^® with 3 mol L^?1 HNO₃ as the carrier. Plutonium(VI) was adsorbed onto the resin, and interfering elements were removed by rinsing the column with 3 mol L^?1 HNO₃. Subsequently, the adsorbed Pu(VI) was eluted with 0.01 mol L^?1 HNO₃, and then introduced directly into the flow-through electrolysis cell with boron-doped diamond electrode. The eluted Pu(VI) was detected by an electrochemical amperometric method at a working potential of 0.1 V (vs. Ag/AgCl). The current produced on reduction of Pu(VI) was continuously monitored and recorded. The plutonium concentration was calculated from the relationship between the peak area and concentration of plutonium. The relative standard deviation of ten analyses was 1.1% for a plutonium solution of 25 μg L^?1 containing 50 ng of Pu. The detection limit calculated from three-times the standard deviation was 0.82 μg L^?1 (1.6 ng of Pu).     

Rusty nails adsorb trace plutonium from the environment

Discarded rusty iron objects in the environment adsorb trace plutonium mobilized by oxygenated surface waters (e.g. rain, snow melt). Radiochemical and mass spectrometric analysis of the surface oxide coating of modest collections of rusty nails retrieved from remote locations provides a global fallout plutonium signal of up to 2 × 10¹⁰ atoms of ²³⁹Pu per sample. The median ²³⁹Pu measurement for 10 samples from five locations was 2.82 × 10⁹ atoms. The average ²⁴⁰Pu/²³⁹Pu atom ratio was 0.176 ± 0.012, consistent with the value accepted for global fallout.     

Use of ionic liquid based chitosan as sorbent for preconcentration of fluoroquinolones in milk,egg, fish,bovine, and chicken meat samples by solid phase extraction prior to HPLC determination

The possibility of using ionic liquid based chitosan sorbent for the separation and preconcentration of fluoroquinolone antibiotics (marbofloxacin, enoxacin, ofloxacin, ciprofloxacin, and enrofloxacin) has been studied. For this reason, different ionic liquids were prepared and coated on the chitosan sorbent. The conditions of the preconcentration of fluoroquinolones on a microcolumn have been optimized and the extraction efficiencies of the prepared sorbents have been compared. The compounds were eluted with 5 mL of 20% NH₃ (v/v, MeOH) solution and determined by HPLC with diode array and fluorescence detector. The limits of detection were found as 4.23 µ g L^?1 for marbofloxacin, and 1.09 µg L^?1 for enoxacin; 3.23 × 10^?3 µg L^?1 for ofloxacin; 8.39 × 10^?3 µg L^?1 for ciprofloxacin; and 19.50 × 10^?3 µg L^?1 for enrofloxacin. The developed method was applied for the analysis of fluoroquinolone in milk, egg, fish, bovine, and chicken samples and the recoveries were obtained in the range 70–100%.     

Removal of environmental level of 239+240Pu and 241Am from groundwater by using humic coated colloidal suspension of goethite (α-FeO(OH))

In case of natural catastrophic nuclear accident scenario like Daiichi Nuclear Power Plant (NPP) Fukushima, Japan (11 March 2011) and industrial nuclear accidents like Chernobyl, USSR (March 1986), thousands of curies of activity goes in the public domain and contaminate the drinking water system in the area around the accidental zone. In view of this there is a need to evolve methodology for decontamination of the drinking water without compromising the drinking water quality. During this work humic coated colloidal suspension of geothite(α-FeO(OH)) followed by ultrafiltration were used to decontaminate the water having ^239+240Pu and ²⁴¹Am in the concentration range of 10–100 Bq L^?1. Polydispersive colloids of goethite were generated by controlled oxidation of FeSO₄ in the presence of NaOH. Size characterization, morphology and elemental profiling of goethite suspension and their aggregation with increase in the concentration of humic acid was studied by using dynamic light scattering and scanning electron microscope hyphenated with energy dispersive spectrometry. Experimental results clearly indicate preferential association of Pu and Am with goethite suspension dominated with 30 nm colloids. The impact of humus material on selectivity of Pu and Am by goethite was studied in the concentration range of 10–100 μg mL^?1 of humic acid. This selectivity is further enhanced linearly with the increase in concentration humic acid from 10 to 60 μg mL^?1 and thereafter it remains constant. Goethite suspension having a coating of 60 μg mL^?1 of humic acid was successfully utilized to decontaminate the water. Goethite suspension was separated from the groundwater using Ultra filtration cell with membrane having 500 NMWL (nominal molecular weight limit).     

Preconcentration of trace environmental plutonium from iron oxide matrix using DIPEX® extractant

This paper summarizes a new method for preconcentration of rusty metal samples using DIPEX^® Actinide Resin from Eichrom Technologies prior to analysis for trace environmental actinides. This method allows for preconcentration of actinides for which the existing lanthanum coprecipitation method is ill-suited. The new and existing methods were shown to provide comparable results for plutonium analysis. Performance was compared for both lab-prepared controls and environmental samples. Using actinide resin, a mean ²³⁸Pu activity of 46 ± 13 % mBq (2σ) was measured, while ²³⁸Pu activity of 40 ± 6 % mBq (2σ) was measured using lanthanum coprecipitation. Small quantities of ^239+240Pu, likely attributable to fallout, were also detected.     

Determination of the plutonium concentration by isotope dilution mass spectrometry using239Pu as a spike

A method is described for the determination of plutonium concentration in the presence of a bulk of other impurities by isotope dilution mass spectrometry /IDMS/ using²³⁹Pu as a spike. The method involves the addition of²³⁹Pu spike / 90 atom%/ to samples with²³⁹Pu / 70 atom%/ and vice versa. After ensuring chemical exchange between the sample and the spike isotopes, plutonium is purified by conventional anion exchange procedure in 7M HNO₃ medium.²³⁹Pu/²⁴⁰Pu atom ratio in the purified spiked sample is determined with high precision /better than 0.1%/ using a thermal ionization mass spectrometer. Concentration of plutonium in the sample is calculated from the changes in²³⁹Pu/²⁴⁰Pu atom ratio in the spiked mixture. Results obtained on different plutonium samples using²³⁹Pu as a spike are compared with those obtained by the use of²⁴²Pu spike. Precision and accuracy comparable to those achieved by using²⁴²Pu are demonstrated. The method provides an alternative in the event of non-availability of enriched²⁴²Pu or²⁴⁴Pu required in IDMS of plutonium and at the same time, offers certain advantages over the use of²⁴²Pu or²⁴⁴Pu spike.     

Uranium in groundwater from Western Haryana,India

This study was undertaken to assess uranium in groundwater and radiological and chemical risks associated with its ingestion in rural habitats in the vicinity of proposed nuclear power project in Western Haryana, India. Uranium concentration in the groundwater of the study area varied from 0.3 to 256.4 μg L^?1. Radiological risk calculated in the form of average life time dose was found 5.1 × 10^?2 mSv to the residents of the area from the ingestion of groundwater. The average cancer mortality and average cancer morbidity risk were calculated to be 4.9 × 10^?6 and 7.7 × 10^?6 respectively indicating the absence of carcinogenic risks. Chemical risk was in the range of 0.02–18.8 µg kg^?1 day^?1. Hazard quotient for 72 % samples was greater than unity which indicates health risk due to chemical toxicity of uranium in groundwater. The results indicate that uranium concentrations in the groundwater of the study area are important due to chemical risk than radiological risk.     

Synthesis and application of polythiophene-coated Fe3O4 nanoparticles for preconcentration of ultra-trace levels of cadmium in different real samples followed by electrothermal atomic absorption spectrometry

In this research, magnetic Fe₃O₄ nanoparticles were synthesised by co-precipitation method and modified with polythiophene (PT) to produce Fe₃O₄-PT nanoparticles for preconcentration and determination of cadmium (??) ion followed by electrothermal atomic absorption spectrometry. The results of FT-IR spectroscopy, EDX analysis and SEM images show that Fe₃O₄-PT nanoparticles were synthesised successfully. Different parameters such as sample pH, amounts of adsorbent, sample volume, extraction time, type and concentration of eluent and desorption time were completely investigated and optimum conditions were selected.

Under the optimum conditions, the calibration curve was linear in the range of 0.01–0.25 µg L^?1 of cadmium (??). The relative standard deviation was 4.7% (n = 7, 0.10 µg L^?1 Cd²⁺) and limit of detection was 3.30 ng L^?1. The accuracy of the proposed method was verified by the analysis of a certified reference material and spike method. Finally, the proposed method was applied for the determination of ultra-trace levels of cadmium (??) in different water and food samples.     

Study on the rate of plutonium vertical migration in various soil types of Lublin region (Eastern Poland)

Soil contamination level with ^239+240Pu of Lublin region was determined using the alpha spectrometric method. Results were compared with similar data from the study performed 15 year earlier. Decrease in total ^239+240Pu concentration and reducing quantity of Chernobyl fraction (up to almost negligible value of 1 %) has been observed in upper soil layer. Determination of ^239+240Pu concentration in soil profile layers allows calculating a vertical migration velocity of plutonium applying a compartment migration model. It was found that ^239+240Pu migration rate varies depending on soil type from 0.29 cm year^?1 in Podsols to 0.58 cm year^?1 in Fluvisols with mean value of 0.5 cm year^?1.     

Multi‐Walled Carbon Nanotubes as Sorbent for Flow Injection On‐Line Microcolumn Preconcentration Coupled with Flame Atomic Absorption Spectrometry for Determination of Cadmium and Copper

Abstract

Multi‐walled carbon nanotubes (MWNTs) were used as sorbent for flow injection (FI) on‐line microcolumn preconcentration coupled with flame atomic absorption spectrometry (FAAS) for determination of trace cadmium and copper in environmental and biological samples. Effective preconcentration of trace cadmium and copper was achieved in a pH range of 4.5–6.5 and 5.0–7.5, respectively. The retained cadmium and copper were efficiently eluted with 0.5 mol L^?1 HCl for on‐line FAAS determination. The MWNTs packed microcolumn exhibited fairly fast kinetics for the adsorption of cadmium and copper, permitting the use of high sample flow rates up to at least 7.8 mL min^?1 for the FI on‐line microcolumn preconcentration system without loss of the retention efficiency. With a preconcentration time of 60 sec at a sample loading flow rate of 4.3 mL min^?1, the enhancement factor was 24 for cadmium and 25 for copper at a sample throughput of 45 h^?1. The detection limits (3σ) were 0.30 and 0.11 µg L^?1 for Cd and Cu, respectively. The precision (RSD) for 11 replicate measurements was 2.1% at the 10‐µg L^?1 Cd level and 2.4% at the 10‐µg L^?1 Cu level. The developed method was successfully applied to the determination of trace Cd and Cu in a variety of environmental and biological samples.     

Determination of Hydrogen Peroxide Using a Novel Sensor Based on Fe3O4 Magnetic Nanoparticles

Fe₃O₄ magnetic nanoparticles were synthesized by chemical co-precipitation with sodium citrate as a surfactant and were used with chitosan to construct a novel hydrogen peroxide sensor. The electrochemical behavior of hydrogen peroxide at the sensor was investigated by cyclic voltammetry. The composite film electrocatalyzed the reduction of hydrogen peroxide, and the peak current increased linearly with concentration from 1.00 × 10^?5 to 1.00 × 10^?3 mol · L^?1 (R = 0.9974) with a detection limit of 1.53 × 10^?6 mol · L^?1. This novel nonenzyme sensor provided good sensitivity, stability, and precision with potential applications.     

Separation of plutonium from uranium using reactive chemistry in a bandpass reaction cell of an inductively coupled plasma mass spectrometer

Oxygen and ammonia were evaluated as reaction gases for the chemical separation between uranium and plutonium in the bandpass reaction cell or dynamic reaction cell (DRC) of the ELAN DRC II mass spectrometer. Both uranium and plutonium demonstrated similar reactivity with oxygen giving rise to corresponding oxides. At the same time, remarkable selectivity in the reaction with ammonia was observed. While uranium was rapidly converted into UNH ₂⁺ and UN₂H ₄⁺ , plutonium remained unreactive in the DRC pressurized with ammonia. This difference in the reactivity allowed the determination of plutonium isotopes in urine and water samples containing excess uranium without preceding separation procedure. Detection limits of 0.245, 0.092, 0.270 and 0.237 ng L^–1 were obtained for ²³⁸Pu, ²³⁹Pu, ²⁴⁰Pu and ²⁴²Pu, respectively, in urine spiked with 10 g L^–1 of U.     

Voltammetric analysis of Pb(II) in natural waters using a carbon paste electrode modified with 5-mercapto-1-methyltetrazol grafted on hexagonal mesoporous silica

A hexagonal mesoporous silica (HMS) functionalized with a 5-mercapto-1-methyltetrazole derivative was employed to prepare a chemically modified carbon paste electrode for Pb(II) detection in aqueous solution by square wave adsorptive stripping voltammetry. The optimal operating conditions were 5 min preconcentration time at pH 6.5, and 120 s electrolysis time in 0.2 mol L^?1 HCl. Under these conditions, the voltammetric signal increased linearly with the preconcentration time in the range 1 to 10 min and with the Pb(II) concentration in the range 1 to 100?µg L^?1. The electrode was reproducible and sensitive. Simultaneous determination of Pb, Cd and Cu was also carried out with the electrode. The accuracy of the method was validated by analysing Pb(II) in tap water and groundwater samples.     

A new sensitive and selective sensor for heavy metal ions based on tannin extracted from the skin of Punica granatum L

This article presents the development of a sensor made from a gold electrode and a receiving polymeric membrane based on tannin extracted from the skin of Punica granatum. L (pomegranate) for real-time detection of heavy metals in a hydrous environment. The basic principle of this device is the complexing (chelating) of metal ions through the adjacent hydroxyl groups contained in the chemical structures of the tannins. The electrochemical characterisation was performed by using electrochemical impedance spectroscopy and square wave voltammetry. Other morphological and structural analyses were performed by using Fourier transform infrared spectroscopy and atomic-force microscopy. The results obtained showed the high sensitivity of the developed device (detection limits of 6.35 × 10^?9 g L^?1 for Cu²⁺, 1.1 × 10^?8 g L^?1 for Cd²⁺ and 2 × 10^?7 g L^?1 for Pb²⁺) and the possibility of simultaneously detecting several heavy metals, each one in a highly selective manner with highly acceptable response time (48s).     

Simple and fast voltammetric procedure of U(VI) determination in the presence of high concentrations of surface active substances

In this work, a simple and fast procedure for elimination of interfering surface active substances and for U(VI) adsorptive stripping voltammetric determination was developed. The adsorption in the form of U(VI)-cupferron complexes was performed, because as it was proved before, U(VI) forms with cupferron stable complexes, which were employed in voltammetric procedures. The procedure is based on two steps: the first is an adsorption of surface active substances onto an Amberlite XAD-16 or XAD-7 resin and the second is a voltammetric determination of U(VI) with a pulsed potential of accumulation alternate –0.65–0.3 V with the frequency of 0.5 Hz and then the differential pulse voltammogram was recorded, whereas the potential was scanned from –0.65 to –1.2 V. The detection limit estimated from three times the standard deviation for a low U(VI) concentrations was equal to 1.7 × 10^?10 mol L^?1 (7.2 × 10^?8 g L^?1). The linear range of U(VI) was observed over the concentration range from 5.0 × 10^?10 mol L^?1 (2.1 × 10^?7 g L^?1) to 2.0 × 10^?8 mol L^?1 (8.5 × 10^?6 g L^?1) for an accumulation time of 60 s. The influence of different kinds of surfactants, such as non-ionic, cationic and anionic on the uranium voltammetric signal was studied. The results confirm the possibility of U(VI) determination in water samples containing high concentrations of surface active substances even up to 50 mg L^?1.     

Preconcentration of trace amounts of cobalt (II) ions in water and agricultural products samples using of 5-(4-dimethylaminobenzylidene) rhodanin modified SBA-15 sorbent prior to FAAS determination

In the present study, the ?5-(4-dimethylaminobenzylidene)rhodanin-modified SBA-15? was applied as stable solid sorbent for the separation and preconcentration of trace amounts of cobalt ions in aqueous solution. SBA-15 was modified by ?5-(4-dimethylaminobenzylidene)rhodanin reagent. The sorption of Co²⁺ ions was done onto modified sorbent in the pH range of 6.8–7.9 and desorption occurred in 5.0 mL of 3.0 mol L^?1 HNO₃. The results exhibit a linear dynamic range from 0.01 to 6.0 mg L^?1 for cobalt. Intra-day (repeatability) and inter-day (reproducibility) for 10 replicated determination of 0.06 mg L^?1 of cobalt was ±1.82% and ?±1.97%?. Detection limit was 4.2 µg L^?1 (3S_b, n = 5) and preconcentration factor was 80. The effects of the experimental parameters, including the sample pH, flow rates of sample and eluent solution, eluent type and interference ions were studied for the preconcentration of Co²⁺. The proposed method was applied for the determination of cobalt in standard samples, water samples and agricultural products.     

Rapid determination of 239Pu in urine samples using molecular recognition technology product AnaLig®Pu-02 gel

This paper describes the use of IBC′s AnaLig^®Pu-02 molecular recognition technology product to effectively and selectively pre-concentrate, separate and recover plutonium from urine samples. This method uses two-stage column separations consisting of two different commercial products, Eichrom’s Pre-filter Material and AnaLig^®Pu-02 resin from IBC Advanced Technologies. By eliminating the co-precipitation techniques and the ashing steps to remove residual organics, the analysis time was reduced significantly. The method was successfully tested by adding known activities of reference solutions of ²⁴²Pu and ²³⁹Pu to urine samples.     

Plutonium oxidation state distribution in natural clay and goethite

Distribution of Pu(IV) and Pu(V) oxidation states at trace initial concentrations (10^?10–10^?11 mol L^?1) was studied in a liquid- and solid-phase of natural clay and goethite systems. Experiments showed an increase in the concentration of Pu(III) up to 11% at pH 5 in solids of the natural clay ?0.1 mol L^?1 NaNO₃ system containing Pu(IV) after 7-day contact. A kinetic sorption/reduction experiment with goethite suspensions (0.01 mol L^?1 NaNO₃ containing Pu(V)) indicated the presence of Pu(III) in the solids up to 15%.     

A New Flow‐Injection Chemiluminescence Method for the Determination of Acyclovir and Gancyclovir

Abstract

A rapid and sensitive flow‐injection chemiluminescence (FI‐CL) method, which is based on the CL intensity that generated from the redox reaction of Ce(IV)‐rhodamine B in H₂SO₄ medium, for the determination of acyclovir and gancyclovir is described. For acyclovir, the determination range is 3×10^?8 g mL^?1–7×10^?5 g mL^?1, with 1.56×10^?8 g mL^?1 as its determination limit. During 11 repeated measurements for 1×10^?6 g mL^?1 acyclovir, the relative standard deviation was 2.08%. For gancyclovir, the determination range was 5×10^?8 g mL^?1–7×10^?5 g mL^?1, with 2.35×10^?8 g mL^?1 as its determination limit. The relative standard deviation is 2.83% with 11 repeated measurements of 1×10^?6 g mL^?1 gancyclovir. This method can be successfully used to determine the content of acyclovir and gancyclovir in injections, acyclovir in eye drops, and, maybe, also for other ciclovirs.