Colloidal behavior of carrier-free125mTe in aqueous solutions

NaCl solutions containing carrier-free^125mTe(IV) and^125mTe(VI) have been prepared. The effect of the presence of various substances on the colloidal behavior of^125mTe in solution has been studied by ultracentrifugation. It has been found that phosphate, sulfide and oxalate ions which complex with various elements decrease the colloidal formation of^125mTe. In order to estimate the size of colloidal particles, the NaCl solutions containing carrier-free^125mTe have been microfiltered through membrane filters with various pore size.     

Adsorption and colloidal behaviour of traces of tellurium(IV) in aqueous solutions

Various NaCl solutions containing traces of tellurium(IV) have been prepared. The effects of tellurium(IV) concentration and pH on the adsorption of tellurium(IV) on filter paper have been studied by filtration method. The effects of NaCl concentration, tellurium(IV) concentration and pH on the formation of a colloid have been also studied by ultracentrifugation and ultrafiltration methods. It has been found that tellurium(IV), at concentrations below about 10^–10M, in neutral NaCl solutions is adsorbed on filter paper and shows colloidal behaviour.     

The chemical states of tellurium produced by spontaneous fission of252Cf

The distribution of the chemical states of tellurium isotopes produced by²⁵²Cf spontaneous fission, collected separately in the matrixes of NaCl, Kl, NaF, CH₃COONa·3H₂O, Na₂SO₄ and NaNO₃ crystals have been investigated. Two chemical states of tellurium isotopes maintained in these matrixes are Te(IV) and Te(VI). The relationships between the distribution of the chemical states of tellurium isotopes and the produced mode of tellurium, the chemical properties of collection matrixes, the time for collecting fission fragments are studied and the possible mechanism of the interactions of the fission products and the matrixes is discussed. The results show that the distribution of chemical states of tellurium isotopes depends on the chemical properties of the collection matrixes mainly.     

Equilibrium in water-peroxide solutions of cesium tellurate studied by 125Te NMR spectroscopy

Water-peroxide solutions of cesium tellurate have been studied by ¹²⁵Te NMR. The system contains different Te(VI) anionic species in equilibrium with one another, including those with coordinated peroxo and hydroperoxo groups.     

Speciation analysis of tellurium by solid-phase extraction in the presence of ammonium pyrrolidine dithiocarbamate and inductively coupled plasma mass spectrometry

Under acidic conditions tellurium(IV) formed a complex with ammonium pyrrolidine dithiocarbamate (APDC). The tellurium(IV) complex was completely retained on a non-polar Isolute silica-based octadecyl (C(18)) sorbent-containing solid-phase extraction (SPE) cartridge, while the uncomplexed Te(VI) passed through the cartridge and remained as a free species in the solution. Only partial Te(IV) was retained on the SPE cartridge for samples without addition of APDC. On the basis of different retention behaviours of the complexed Te(IV) and uncomplexed Te(VI), a simple and highly sensitive method is proposed for the determination of total tellurium and Te(VI) by SPE separation and inductively coupled plasma mass spectrometry (ICP-MS) detection. The Te(IV) concentration was calculated as the difference between total tellurium and Te(VI) concentrations. The detection limit (3 sigma) is 3 ng L(-1) tellurium. Factors affecting the separation and detection of tellurium species were investigated. Coexisting ions did not show significant interferences with the Te(IV)-APDC complex retention and the subsequent ICP-MS detection of Te. The method has been successfully applied to the tellurium speciation analysis in waters with spiked recoveries for Te(IV) and Te(VI) of 86.0-108% and 87.1-97.4%, respectively.     

Sorption and separation of some elements of nuclear importance using Chelex-100

Chelex-100, in the anionic form has been studied for its ability to perform selective separation and concentration of some metal ions of nuclear importance from mineral acid solutions. The sorption behavior of Zr(IV)–Nb(V), Mo(VI), Tc(VII), Te(IV) and U(VI) from solutions of hydrochloric and sulphuric acids on Chelex-100 has been studied under static and dynamic conditions. Mo(VI) and Tc(VII) have been concentrated on the resin from hydrochloric or sulphuric acid solutions at low acidities probably, as the anions MoO ₄ ^2– and TcO ₄ ^– , respectively. Te(IV) has been isolated from hydrochloric acid solutions of normalities 6 in the form of the anionic chloro complex TeCl ₆ ^2– . Optimum conditions for elution and separation of Mo(VI), Tc(VII), Te(IV) and U(VI) were recommended.     

First example of the correlated calculation of the one‐bond tellurium–carbon spin–spin coupling constants: Relativistic effects,vibrational corrections,and solvent effects

This work reports on the comprehensive calculation of the NMR one‐bond spin–spin coupling constants (SSCCs) involving carbon and tellurium, ¹J(¹²⁵Te,¹³C), in four representative compounds: Te(CH₃)₂, Te(CF₃)₂, Te(C?CH)₂, and tellurophene. A high‐level computational treatment of ¹J(¹²⁵Te,¹³C) included calculations at the SOPPA level taking into account relativistic effects evaluated at the 4‐component RPA and DFT levels of theory, vibrational corrections, and solvent effects. The consistency of different computational approaches including the level of theory of the geometry optimization of tellurium‐containing compounds, basis sets, and methods used for obtainig spin–spin coupling values have also been discussed in view of reproducing the experimental values of the tellurium–carbon SSCCs. Relativistic corrections were found to play a major role in the calculation of ¹J(¹²⁵Te,¹³C) reaching as much as almost 50% of the total value of ¹J(¹²⁵Te,¹³C) while relativistic geometrical effects are of minor importance. The vibrational and solvent corrections account for accordingly about 3–6% and 0–4% of the total value. It is shown that taking into account relativistic corrections, vibrational corrections and solvent effects at the DFT level essentially improves the agreement of the non‐relativistic theoretical SOPPA results with experiment. © 2016 Wiley Periodicals, Inc.     

Determination of selenium and tellurium in air by atomic-absorption spectrometry

Elemental selenium and tellurium, and gaseous inorganic forms of Se(IV), Se(VI), Te(IV) and Te(VI) have been determined after their adsorption on gold-coated beads. After leaching, with water and dilute hydrochloric and nitric acids, the different chemical species in each acid fraction were separated with an anion-exchange resin (Bio-Rad AG-1X8) and a cation-exchange resin (Amberlite IR-120 Plus) by varying the acidity of the leaching agent. Subsequent analysis was by graphite-fumace atomic-absorption spectrometry. The lower detection limit for Se and Te was 0.03 ng/M(3) with a precision of +/- 5%. The average amounts of selenium in interior and exterior air samples were about 4.73 and 1.93 ng/m(3) respectively. For tellurium the corresponding values were about 0.78 and 0.24 ng/m(3).     

Preparation of a118Te/118Sb radionuclide generator

The development of a new radionuclide generator, based on¹¹⁸Te/¹¹⁸Sb, has been studied. The 3.5 minute¹¹⁸Sb daughter activity decays principally by positron emission and has potential use as a flow tracer. The¹¹⁸Te parent is conveniently produced by proton bombardment of antimony targets. A simple and efficient scheme for the separation of radiotellurium from proton-irradiated antimony targets has been developed, and thin-target cross sections for¹²¹Sb(p, 4n)¹¹⁸Te and competing reactions have been determined. For antimony targets irradiated with 46 MeV protons, the yields (mCi/g Ah) of¹¹⁸Te,^119mTe and¹¹⁹Te were measured to be 0.71, 0.33 and 1.9, respectively. The adsorption and elution characteristics of activated carbon for tellurium have been evaluated for use as a column chromatography adsorbent in a¹¹⁸Te/¹¹⁸Sb generator. The conditions for optimal¹¹⁸Sb elution and minimal¹¹⁸Te breakthrough for promising systems are presented.     

123mTe as a calibration standard for123I

A method preparing solutions of a mixed chloro, bromo-complex of tellurium labeled with^123mTe is described. The solutions are shown to be excellent standards for calibrating radioisotope dose calibrators used to measure¹²³I.     

Electrochemistry of tellurium(IV) in KCl−AlCl3 melts

The reduction of Te(IV) at tungsten electrodes in basic and neutral KCl?AlCl₃ melts has been studied in the temperature range from 300 to 400°C using cyclic voltammetry and differential pulse polarography. In basic melts Te(IV), present as TeCl₆^2? and TeCl₅^?, is reduced to soluble Te(II) species, which can be further reduced to elementary tellurium insoluble in tungsten. The divalent species are stabilized by increasing the temperature. From the pCl^? dependence of the reduction process, Te(II) in basic melts is suggested to be present as TeCl₃^? and TeCl₂. In neutral melts a third oxidation state (possibly monovalent tellurium) is formed when Te(II) is reduced.     

Separation of carrier-free115mIn from115Cd and132I from132Te over the zirconium oxide column

A new way of radiochemical separation of carrier-free^115mIn from¹¹⁵Cd and¹³²I from¹³²Te over the column of zirconium oxide is described. Activities of Cd and In in equilibrium in dilute acetic acid solution were bufferred with dilute sodium acetate and fed into the column at a pH 7, when cadmium activity passed out unadsorbed and the^115mIn was adsorbed in the column. A study of the γ-ray peak of the separated^115mIn showed that the product is of high radionuclidic purity. Te-I pair was separated by passing the weakly acidic solution of¹³²Te and¹³²I in the presence of AgNO₃ and Na₂SO₃, through the column where both activities were adsorbed. Iodine was washed outh with 5% sodium thiosulphate solution and the retained tellurium activity was later washed out with 6M HNO₃. The β-decay study showed that the separated¹³²I product is of high radiochemical purity. The processes took less than half an hour and the yields were quantitative.     

Simple potentiometric method for determination of specific activity of carrier-free125I with the aid of ion-selective membrane electrode

A simple potentiometric method for determination of specific activity of carrier-free¹²⁵I (NaI) has been elaborated. The method is based on the measurement of tracer amounts of iodide present in the¹²⁵I preparate, by using an ion-selective membrane electrode. The method presented is suitable in practice for rapid estimation of specific activity of carrier-free¹²⁵I preparation in cases where the knowledge of its numerical value is necessary.     

113Sn-113mIn generator with a glass beads column

The adsorption characteristics of ¹¹³Sn(IV) and ^113mIn(III) on glass beads from NaCl solutions have been studied. On the basis of these studies, ¹¹³Sn-^113mIn generator has been prepared by adsorbing ¹¹³Sn on the glass beads column. ^113mIn has been eluted by the 0.16M NaCl solution with pH 3.0, remaining ¹¹³Sn adsorbed on the glass beads. The yield of ^113mIn has been about 73% in the first 6 ml of eluate, while the breakthrough of ¹¹³Sn has been about 0.042%.     

Dünnschichtchromatographie als Hilfsmittel in der radiochemie. 6. Mitteilung. 1. Trennung von Sn, 125Sb und 125mTe. - 2. Trennung von As,Sb und Sn

1. Thin-layer chromatography is applied to the separation of the nuclids of the decay-chain: ¹²⁵Sn → ^125mTe. Different factors influencing the separation are investigated. The method can be used for the carrier-free separation of ^125mTe. 2. As, Sb and Sn have been separated by thin-layer chromatography.     

Tellurium Chloride Complexes in Nonaqueous Solutions

Tellurium(IV) complexes (R₄N)₂[TeCl₆] (T6), (R₄N)[TeCl₅] (T5), and (R₄N)[TeCl₄OH] (T4), where (R₄N)⁺ is tetrabutyl, tetraoctyl, and trialkyl benzyl ammonium cations, were synthesized. Tellurium distribution between aqueous HCl solutions and trialkyl benzyl ammonium chloride solution in caprylic acid was studied. The ¹²⁵Te NMR spectra of aqueous HCl solutions of tellurium have a single averaged peak, whose chemical shift (CS) depends on the acid concentration. ¹²⁵Te NMR spectroscopy has shown that the T4 complex in nonaqueous solutions is kinetically inert and the ligand exchange with the T6 and T5 complexes is retarded. In contrast, the T5 and T6 complexes, when simultaneously present in nonaqueous solutions, rapidly exchange ligands. ¹²⁵Te NMR, IR, Raman, and UV spectroscopic studies have shown that under standard conditions, the reaction (Bu₄N)[TeCl₅]+Bu₄NCl = (Bu₄N)₂[TeCl₆] G⁰ = -19.1(1 ± 0.3) kJ/mol and H⁰ = -6.5(1 ± 0.2) kJ/mol) takes place in methylene chloride solution. The symmetry groups of the synthesized complexes in the solid state and CSs for tellurium solutions (0.2 gatom/liter Te) in methylene chloride were determined: O_h and –58 ppm for T6; C_4v and +75 ppm for T5; and C_3v and +54 ppm for T4 (CS = 0 for a 0.2 mol/liter TeO₂ solution in 11.4 mol/liter HCl).     

Comparative study of different chromatographic methods for quality control of113mIn-radiopharmaceuticals

Paper chromatography and Gel Chromatography Column Scanning technique (GCS) have been applied for the separation of indium fractions in^113mIn-radiopharmaceuticals. By these techniques the percentage of ionic indium,^113mIn-colloid and^113mIn-compound have been determined. The resolution efficiency of the gels was found to be significantly influenced by the gel type media and the pH of the eluent. The results obtained from the GCS-profiles indicated that the Sephadex G-50 Fine was the best and can be routinely used in the radiochemical quality control of the^113mIn-phytate. Good separation of^113mIn-colloids,^113mIn-microaggregate and^113mIn-phytate from carrier-free^113mIn-eluate was performed using Whatman No. 3, previously washed with 0.04N HCl and developed either with 0.9% NaCl (for^113mIn-colloid), or 85% methanol (for^113mIn-phytate), or phosphate-methanol buffer (for^113mIn-microaggregate) as rapid and simple procedure for determination of the radiochemical quality control of indium compound in the forms of radiocolloids.     

Intestinal absorption of tellurium studied with stable tracers

An investigation on tellurium metabolism by administration of stable tellurium isotopes¹²⁴Te and¹²⁶Te has been performed. Fractional intestinal absorption was determined in rabbits by the double tracer technique. The investigated subjects were given an enriched solution of one tellurium isotope orally and a few minutes later an enriched solution of the other isotope intravenously. The¹²⁴Te and¹²⁶Te contents in plasma samples were determined by proton nuclear activation. The methodology described offers a means to study tellurium metabolism in humans without radiation risk.     

125Te-NMR-spektren von organotellurhalogeniden

Tetraorganotin compounds react with tellurium tetrachloride or tellurium tetrabromide with formation of the corresponding organotellurium trihalides and diorganotellurium dihalides. ¹²⁵Te NMR spectra of the reaction mixtures are used to determine the reaction products.     

A mössbauer investigation of some heterocyclic tellurium compounds

The ¹²⁵Te Mössbauer parameters of some substituted tellurium(II) acetylacetonates are interpreted in terms of their molecular and crystal structures and the population of low energy conduction bands by non-bonding electrons.