Ionophores in Rubidium Ion‐Selective Membrane Electrodes

Binaphthyl‐based crown ethers incorporating anthraquinone, benzoquinone, and 1,4‐dimethoxybezene have been synthesized and tested for Rb⁺ selective ionophores in the poly(vinyl chloride) (PVC) membrane. The membrane containing NPOE gave a better Rb⁺ selectivity than those containing either DOA or BPPA as a plasticizer. The response was linear within the concentration range of 1.0×10^?5–1.0×10^?1 M and the slope was 54.7±0.5 mV/dec. The detection limit was determined to be 9.0×10^?6 M and the optimum pH range of the membrane was 6.0–9.0. The ISE membrane exhibits good selectivity for Rb⁺ over ammonium, alkali metal, and alkaline earth metal ions. Selectivity coefficients for the other metal ions, log K^Pot were ?2.5 for Li⁺, ?2.4 for Na⁺, ?2.0 for H⁺, ?1.0 for K⁺, ?1.2 for Cs⁺, ?1.6 for NH₄⁺, ?4.5 for Mg²⁺, ?5.0 for Ca²⁺,?4.9 for Ba²⁺. The lifetime of the membrane was about one month.     

Application of Nafion／Cobalt Hexacyanoferrate Chemically Modified Electrodes for the Determination of Electroinactive Cations by Ion Chromatography

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Anthropogenic radiotracers assessment as tool to environmental compliance rules and management

A framework, within models and studies can be applied, to develop coherent and logical environmental impact management methodologies for ionizing radiation, is essential. A number of components, which form the basis for such a system, included the dilution factor for radioactive liquid effluent releases. In this study we established a strategic, fast and cheap methodology to estimate the dilution factor for the release of liquid radioactive effluents at IPEN. The radioisotopes ³H, ⁵⁴Mn, ⁶⁰Co, ⁶⁵Zn, and ¹³⁷Cs, generated in the routine operation of the Research Reactor IEA-R1, were used as radiotracers. The generated liquid radioactive effluent was stored in a 300 m³ capacity tank. The initial concentration of its present radioisotopes were determined. A planned release of effluent from the storage tank was carried-out. Simultaneously, the sampling was made upstream of the storage tank discharge point and the concentration ³H, ⁵⁴Mn, ⁶⁰Co, ⁶⁵Zn and ¹³⁷Cs in the mix sewerage system discharge point E1 at IPEN were monitored. The estimated dilution factor of discharge point of the aqueous effluent for ³H was 4.3 and 7.4, ⁵⁴Mn was12 and 16.1, ⁶⁰Co was 12.6 and 14.2, ⁶⁵Zn was 12 and 27.9 and ¹³⁷Cs was 6.2 and 13.9, respectively.     

Selective Recovery of Nonferrous Metal Cations from Wastewater with Weakly Basic Anion Exchangers

Selective recovery of transition metals (Ni^{2 +}, Cu^{2 +}, and Cr^{2 +}) with weakly basic anion exchangers from aqueous solutions simulating naturally mineralized water was studied. The exchange capacity of anion exchangers for these cations was determined. The technique for efficient resin regeneration was developed.     

Determination of hydrogen ion by ion chromatography (IC) with sulfonated cation-exchange resin as the stationary phase and aqueous EDTA (ethylenediamine-N,N,N′,N′-tetraacetic acid) solution as the mobile phase

An ion chromatographic (IC) method has been developed for determination of hydrogen ion (H⁺). It is based on the use of sulfonated cation-exchange resin as stationary phase, aqueous ethylenediamine-N,N,N′,N′-tetraacetic acid (dipotassium salt, EDTA-2K, written as K₂H₂Y) solution as mobile phase, and conductivity for detection. H⁺ was separated mainly by cation-exchange, but its elution was accelerated by the presence of EDTA. The order of elution for the model cations was H⁺ > Li⁺ > Na⁺ > NH₄ ⁺ > Ca²⁺ > > Mg²⁺. A sharp and highly symmetrical peak was obtained for H⁺ and this was attributed to the capacity of H₂Y₂ ^2– to receive and bind H⁺. H⁺ was detected conductiometrically and detector response (reduction in conductivity as a result of H⁺+H₂Y^2–→H₃Y^–) was linearly proportional to the concentration of H⁺ in the sample. The detection limit for H⁺ with this IC system was better than 4.7 μmol L^–1. A significant advantage of this method was the ability to separate and determine, in one step, H⁺ and other cations. The successful determination of H⁺ and other cation species in real acid-rain samples demonstrated the usefulness of this method.     

Catalytic Adsorptive Stripping Voltammetry of Cobalt in the Presence of Dimethylglyoxime and Nitrite at In Situ Plated Lead–Copper Film Electrode

A lead‐copper film electrode was proposed for Co(II) determination by catalytic adsorptive stripping voltammetry. The electrode was plated in situ and hence the exchange of a solution after plating step was not required. At optimized conditions the calibration graph for Co(II) was linear from 5×10^?10 to 2×10^?8 mol L^?1 for accumulation time of 15 s. The relative standard deviation for Co(II) determination at concentration 5×10^?9 mol L^?1 was 4.1%. The detection limits for Co(II) were 1.2×10^?10 and 1.0×10^?11 mol L^?1 for an accumulation time of 15 and 180 s, respectively. The method was applied to Co(II) determination in certified reference material and other water samples.     

Simultaneous determination of210Bi and210Po on pine needles by solvent extraction and liquid scintillation counting

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.     

Determination of plutonium and its isotopic ratio in marine sediment samples using quadrupole ICP-MS with the shield torch system under normal plasma conditions

An analytical method for determining ²³⁹Pu and ²⁴⁰Pu in marine sediment samples, which uses quadrupole ICP-MS, was developed in this work. A simple anion-exchange chromatography system was employed for the separation and purification of Pu from the sample matrix. A sufficient decontamination factor of 1.4×10⁴ for U, which interferes with the determination of ²³⁹Pu, was achieved. High sensitivity Pu determination was obtained, which led to an extremely low concentration detection limit of ~8 fg/ml (0.019 mBq/ml for ²³⁹Pu; 0.071 mBq/ml for ²⁴⁰Pu) in a sample solution, or an absolute detection limit of 42 fg in a 5 ml sample solution, by using the shield torch technique. Analytical results for the determination of the ^239+240Pu and the ²⁴⁰Pu/²³⁹Pu ratio in IAEA 368 (ocean sediment) reference material indicated that the accuracy of the method was satisfactory. The method developed was successfully applied to a study of Pu behavior in the sediments from Sagami Bay, Japan. The observed high ²⁴⁰Pu/²³⁹Pu ratio in the sediment core indicated that there was additional Pu input derived from close-in fallout in addition to the global fallout.     

Automated production of 64Cu prepared by 18?MeV cyclotron

⁶⁴Cu (T_1/2?=?12,7?h, ??^? 37,1?%, ??⁺ 17,9?%, EC 41?%) is a useful radioisotopes for positron emission tomography radiopharmaceutical. We used the reaction route ⁶⁴Ni(p,n)⁶⁴Cu for the ⁶⁴Cu preparation. A basic disadvantage of this route, a high price of the enriched target material, was eliminated by using very simple recycling procedure. Compact solid target irradiation system was installed at the end of the external beam line of the IBA Cyclone 18/9 cyclotron. In this paper, the irradiation of ⁶⁴Ni target and separation of ⁶⁴Cu from a target material is described. The separation was achieved by anion exchange chromatography with HCl as a elution solution. The distribution ratio for different HCl concentrations on Bio-Rad AG1-X8 and elution profile of ⁶⁴Cu were investigated. ⁶⁴Cu production rate for 100?mg ⁶⁴Ni of 99.09?% purity (ISOFLEX) on gold target was 104?MBq/??Ah. The activity of the product was checked by ionisation chamber (Curiementor), gamma spectrometry using a HPGe detector and liquid scintillation counting using the triple-to-double coincidence ratio method. The separation process of ⁶⁴Cu was made in a home-made separation module.     

Measurement of 241Pu in Environmental Samples

Concentrations of ²⁴¹Pu in the air and deposition samples in Finland after the 1986 Chernobyl accident were estimated with the aid of ingrowth of ²⁴¹Am. Plutonium-241 was clearly shown to be present in the Chernobyl fallout in Finland. Pu was unevenly distributed and the mean radioactivity ratio of ²⁴¹/^239,240Pu was 70 for air and 71 for deposition samples. Here, a radiochemical method for determination of ²⁴¹Pu in the environmental samples was also developed. The method was based on the liquid scintillation measurement of ²⁴¹Pu with a pulse shape analyser after Pu separation. Efficiency calibration was performed with the aid of ³H standard instead of the ²⁴¹Pu standard. The method was tested by comparing the results with the method of ²⁴¹Am ingrowth and some reference samples. The detection limit for ²⁴¹Pu was 0.007 Bq per sample. The ²⁴¹Pu concentrations in the sediment samples taken from the Baltic Sea varied between <0.5 and 27 Bq·kg^-1. The effect of the Chernobyl accident could be seen both from the ²⁴¹Pu concentrations and from the Pu isotope ratios in vertical distributions of sliced samples.     

A new Schiff base fluorescent indicator for the detection of Mg<Superscript>2+</Superscript> and its application to real samples

A new Schiff base fluorescence probe, 3-Allylsalicylaldehyde salicylhydrazone (L), for Mg²⁺ was designed and synthesized. The fluorescence of the sensor L was enhanced remarkably by Mg²⁺ with 2:1 binding ratio, and the binding constant was determined to be 1.02 × 10⁷ M^?1. Probe L had high sensitivity for Mg²⁺ in a solution of DMF/water (4:1, v/v, pH 7.5), and the detection limit was 4.88 × 10^?8 mol/L. Common coexistent metal ions, such as K⁺, Na⁺, Ag⁺, Ca²⁺, Zn²⁺, Ba²⁺, Bi²⁺, Cu²⁺, Ni²⁺, Hg²⁺, Fe³⁺ , and Al³⁺, showed little or no interference on the detection of Mg²⁺ in solution. The fluorescence probe L, which was successfully used for the determination of trace Mg(II) in real samples, was shown to be promising for liquid-phase extraction coupled with fluorescence spectra.     

Amperometric detection studies of Nafion/indium hexacyanoferrate film for the determination of electroinactive cations in ion chromatography

An amperometric detector based on the chemical modification of Nafion and indium (III) hexacyanoferrate (II, III) thin film (Nafion/In-CN-Fe) onto a glassy carbon (GC) electrode, was first successfully used for the determination of electroinactive cations (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, NH₄ ⁺) in single column ion chromatography (IC). A set of well-defined peaks of electroinactive cations was obtained. The detection limits of the cations are 8.9 × 10^–6 mol/L for Li⁺, 2.3 × 10^–6 mol/L for Na⁺, 5.2 × 10^–6 mol/L for K⁺, 4.8 × 10^–6 mol/L for Rb⁺, 4.0 ׶10^–6 mol/L for Cs⁺ and 5.3 × 10^–6 mol/L for NH₄ ⁺ at a single-to-noise ratio of 3. The proposed method was quick, sensitive and simple. The cations in rainwater and mineral water were successfully analyzed by this method.     

Preparation of <Superscript>26</Superscript>Al, <Superscript>59</Superscript>Ni, <Superscript>44</Superscript>Ti, <Superscript>53</Superscript>Mn and <Superscript>60</Superscript>Fe from a proton irradiated copper beam dump

The station for pions cancer therapy was operated at PSI from 1980 to 1992. After a cooling time of 12 years it’s made of copper beam dump was cut and samples were taken for analytical purposes. The sampling collected about 500 g of high active copper chips that can be used for separation of exotic radionuclides. The analyses by gamma spectrometry, LSC and AMS showed main nuclides present to be ⁶⁰Co, ⁵⁴Mn, ²²Na, ⁶⁵Zn, ²⁶Al, ⁵³Mn, ⁵⁹Ni, ⁶³Ni, ⁵⁵Fe and ⁶⁰Fe and ⁴⁴Ti with a daughter nuclide ⁴⁴Sc. In the frame of ERAWAST project a procedure combining selective precipitation and ion exchange for the separation of the rare radionuclides from the copper beam dump was developed. The proposed separation procedure is easy for remote controlled implementation in a hot cell. The ion exchange separation of Ni, Al, Mg, Ti and Fe was complete and high decontamination factors for copper and cobalt were achieved. Based on the developed procedure a remotely controlled system for separation of exotic radionuclides from the copper chips was set up. The full scale system was installed in a hot cell where high activity levels can be handled. In order to evaluate the reliability and functionality of the system extensive tests have been done. During the test period 13.86 g in total of the proton irradiated copper beam dump were processed for separation of ²⁶Al, ⁵⁹Ni, ⁵³Mn, ⁴⁴Ti and ⁶⁰Fe. The results showed that the system was operational and the radionuclide separation was selective with high chemical yield. The procedure manages as well the generated liquid wastes containing high level of ⁶⁰Co activity.     

负载型纳米二氧化钛对重金属离子吸附性能的研究

采用溶胶-凝胶法制备二氧化钛溶胶, 将其浸渍在硅胶上, 合成了负载型纳米二氧化钛材料, 以X射线衍射(XRD)、扫描电镜(SEM)等手段对其进行了表征. 以ICP-AES为检测手段, 系统地研究了负载型纳米TiO₂材料对重金属离子Cd^2＋, Cr^3＋, Cu^2＋和Mn^2＋的吸附性能. 结果表明, 在pH 8～9范围内, 所研究的重金属离子均可被定量富集, 吸附的金属离子可用0.5 mol/L的HNO₃完全解脱. 负载型纳米二氧化钛对Cd^2＋, Cr^3＋, Cu^2＋和Mn^2＋的静态吸附容量分别为8.3, 13.1, 12.6和5.1 mg/g, 与未负载的纳米二氧化钛相近. 将其应用于环境标准样品中Cd^2＋, Cr^3＋, Cu^2＋和Mn^2＋的分离富集与测定, 结果满意.     

Uranium age-dating using in-situ isotope ratios by thermal ionization mass spectrometry for nuclear forensics

The model dates of two enriched uranium materials were determined using a new method for nuclear forensics investigation. In this method, without spike addition, the ²³⁰Th/²³⁴U ratio was calculated from the measured ratios of ²³⁰Th/²³⁴Th and ²³⁴U/²³⁸U and from calculated ²³⁴Th/²³⁸U ratio in secular equilibrium. The model date obtained for the low-enriched uranium material was in agreement with the known production date. For the highly enriched uranium material, a more recent model date than the known production date was obtained. The ²³⁴U interference on ²³⁴Th counting in thermal ionization mass spectrometer measurement was suspected as a potential cause.

     

Radiochemical separation of 82Sr and the preparation of a sterile 82Sr/82Rb generator column

Summary Ion-exchange chromatography using the chelating resins Purolite S950 and Chelex 100 was investigated for the radiochemical separation of ⁸²Sr from a RbCl target. 0.25M NH₄Cl solution was employed for the retention of Sr and elution of Rb, and 2M HCl for the elution of Sr. Although both resins showed very similar results, the conditions for adsorption of Sr were different. The ammonium chloride solution was directly used with Purolite S950 while it was necessary to adjust the pH between 9 and 10 with Chelex 100. Purolite S950 was, therefore, selected for routine production of ⁸²Sr. A procedure has been introduced for the preparation of a hydrous tin dioxide as supporting material for the ⁸²Sr/⁸²Rb generator column. All components of the generator column were made up of stainless steel. The column was 4 cm long, 9.5 mm O.D. and 7.1 mm I.D. Using isotonic saline (0.9% NaCl) for elution of ⁸²Rb, elution curves with different flow rates ranging from 5 to 20 ml/min were obtained. Maximum available ⁸²Rb was eluted in the first 20 ml. The column generator provided a sterile ⁸²Rb in isotonic saline. The breakthrough of ⁸²Sr over 4 weeks of elution using 7 liter of saline was on average 4.5 ^. 10^-5% (based on the first 20 ml eluate).     

Determination of Se(IV) in On‐Line System by Cathodic Stripping Voltammetry

A sensitive and selective on‐line voltammetric procedure for determination of traces of Se(IV) is presented. The pulsed potential accumulation was proposed for minimization of interferences of surface active substances and foreign ions. The calibration plot was linear from 1×10^?9 mol L^?1 to 4×10^?8 mol L^?1 for accumulation time of 180 s. The relative standard deviation was 6.1% (n=5) for a Se(IV) concentration of 1×10^?8 mol L^?1. The detection limit estimated from (3 σ) for an accumulation time of 180 s was about 4×10^?10 mol L^?1. The validation of the procedure proposed was made by a recovery tests for tap and river water samples.     

Development of cost effective method for production of 64Cu from natNi

A ^natNi foil was used for the production of ⁶⁴Cu via ⁶⁴Ni(p,n)⁶⁴Cu nuclear reaction when the necessary investment for target material (350 mg) is 50 times less using the ^natNi instead of ⁶⁴Ni. The produced 32.2 ± 1.8 MBq of “no carrier added” ⁶⁴Cu is sufficient for 10 mice trials on small animal PET. The radionuclide contamination was <13 ± 12 kBq for ⁵⁵Co and 4 ± 2 kBq for ⁵⁷Ni comparing to minimum detectable activity and only 52 ± 2 kBq of ⁶¹Cu was in ⁶⁴Cu due to the modified ion exchange separation. The concentration of Fe(III) was maintained under 1.7 ppm by precipitation and filtering of Fe(OH)₃ due to the chemical purity was required.     

Ion-exchange chromatography using vanadyl and vandate salts as mobile phases with indirect detection

Summary Vanadyl sulfate, VOSO₄, was characterized as the mobile phase for the ion exchange separation of Li⁺, Na⁺, NH ₄ ⁺ , and K⁺ using indirect photometric detection at 254 nm. Detection limits ranged from 0.2 ppm for Li⁺ to 1 ppm for K⁺. Indirect electrochemical detection of these separated cations by reduction of VO (II) to V³⁺ was compared to spectrophotometric detection. The potential of the vanadate species, HVO ₄ ^2– , for the separation of F^–, Cl^–, and SO ₄ ^2– , with indirect photometric detection was also demonstrated.     

Preparation of Cu (II) imprinted polymer electrode and its application for potentiometric and voltammetric determination of Cu (II)

The Cu (II) imprinted polymer glassy carbon electrode (GCE/Cu-IP) was prepared by electropolymerization of pyrrole at GCE in the presence of methyl red as a dopant and then imprinting by Cu²⁺ ions. This electrode was applied for potentiometric and voltammetric detection of Cu²⁺ ion. The potentiometric response of the electrode was linear within the Cu²⁺ concentration range of 3.9 × 10^?6 to 5.0 × 10^?2 M with a near-Nernstian slope of 29.0 mV decade^?1 and a detection limit of 5.0 × 10^?7 M. The electrode was also used for preconcentration anodic stripping voltammetry and results exhibited that peak currents for the incorporated copper species were dependent on the metal ion concentration in the range of 1.0 × 10^?8 to 1.0 × 10^?3 M and detection limit was 6.5 × 10^?9 M. Also the selectivity of the prepared electrode was investigated. The imprinted polymer electrode was used for the successful assay of copper in two standard reference material samples.