Determination Of Rhenium Research Articles

Application of microwave plasma atomic emission spectrometry in bioanalytical chemistry of bioactive rhenium compounds

Five newly synthetized fac-Re(I) tricarbonyl compounds were explored as prospective antitrypanosomal agents. The biological activity of the whole series was evaluated preliminarily against the epimastigote form of Trypanosoma cruzi. All compounds showed activity against epimastigotes with IC50 values in the low micromolar range. The most active compound [fac-Re(I)(CO)3(tmp)(CTZ)](PF6), with CTZ = clotrimazole and tmp = 3,4,7,8-tetramethyl-1,10-phenantroline, showed good selectivity towards the parasites and thus was selected to carry out further metallomic studies. For this task, a newly bioanalytical method based on microwave plasma atomic emission spectrometry (MP-AES) was developed and validated. The accuracy of the method was ensured by testing a certified reference material. Results of rhenium elemental analysis by MP-AES agreed with the proposed formula of the studied compounds, contributing to the overall validation of the method, which was then applied to evaluate the percentage of rhenium uptaken by the parasites and the association of the compounds with parasite biomacromolecules. Metallomics results showed low total rhenium percentage uptaken by parasites (∼1.2%) and preferential accumulation in the soluble proteins fraction (∼82.8%). Thus, the method based on MP-AES turned out to be an economical and green alternative for metallomics studies involving potential rhenium metallodrugs. Moreover, a comparison against rhenium determination by electrothermal atomic absorption spectrometry (ET-AAS) was included.

The use of the short-lived radioisotope <sup>188</sup>Re in the analytical practice of rhenium determination

The possibility of using the short-lived radioisotope 188Re (16.9 h) in the radioactive-tracer technique for estimation of the losses occurred during sample preparation and for analysis of the solutions with a low rhenium content is shown. The radioisotope was obtained in an 188Re generator, which is a glass column filled with aluminum oxide with a pre-adsorbed parent isotope 188W (69.4 days) that forms 188Re during β-decay. The latter in the form of a perrhenate ion was selectively washed into an aqueous solution, which was used to obtain a labeled solution. The values of rhenium losses and their distribution over the stages of sample preparation of carbon-containing raw materials (e.g., high-viscosity oil) including sintering, leaching, filtration and evaporation are estimated. It is shown that the greatest amount of rhenium is lost at the stage of sintering. However, the use of MgO + KMnO4 mixture minimize the losses occurred at this stage and, hence, the total losses of rhenium. A rapid procedure of rhenium determination using the method of radiometric correction with substoichiometric separation is described. The method is based on the quantitative extraction of a stable complex of tetraphenylphosphonium cation (TPhPh) with the perrhenate ion by dichloroethane. The extraction constant of (C6H5)4PReO4 complex is (3.03 ± 0.75) × 106. The extraction of the perrhenate ion not complexing with TPhPh does not exceed 1 – 2 %. The developed method provides rhenium determination in the sample at a level of 1 – 100 μg. A 10-fold excess of Zn2+ and Ni2+ present in a chloride-containing medium affects the determination of rhenium. The anions , , and have the most pronounced interfering effect whereas , , and Cl– do not interfere with the determination.

Determination of rhenium in igneous rock by X-ray fluorescence spectrometry with prior electrochemical concentration

This paper describes a technique for determining rhenium in igneous rock. The technique involves electrochemical concentration of rhenium into solid phase followed by its determination by X-ray fluorescence spectrometry. Compounds of rhenium and other metals were converted into a solution as a result of processing of igneous rock samples with a mixture of nitric and chloric acids. After the resulting solutions had been neutralized, rhenium was electrochemically concentrated by electrodeposition on a cathode. Due to the presence of a considerable amount of iron group metals in the studied samples, it was possible to use induced electroreduction with regard to rhenium, molybdenum and tungsten compounds. As a result, the refractory metals converted into a cathode deposit and thus were effectively concentrated into solid phase. The detection limit for rhenium in the solution is ~2 mcg/L. Considering the complex chemical composition of the analyzed samples, spike test appears to be the best solution for quantitative determination of rhenium. The developed technique allows to determine the concentration of rhenium with the concentration of molybdenum being ten times in excess. The latter is typical of igneous rock samples. More than 100 samples taken from Kudryavy volcano were analyzed in the study: the concentration of rhenium in the samples was within 0.5 to 50 g/t. For the sake of verification, the obtained data were compared against the results of inductively coupled plasma mass spectrometry (ICP-MS). The comparison showed a good convergence. At the same time, lower values would be systematically obtained when using inductively coupled plasma atomic emission spectrometry (ICPAES). The developed technique can be used to determine rhenium and molybdenum in rock. The authors would like to thank O. A. Nabelkin, a research fellow at the Institute of Mineralogy, Geochemistry and the Crystal Chemistry of Rare Elements, for his help with the adoption of X-ray fluorescence spectrometry, and R. G. Chumakov, Candidate of Physical and Mathematical Sciences, a senior researcher at the National Research Centre Kurchatov University, for his help with the X-ray photoelectron spectroscopy studies.This research was carried out using the funds assigned to D. Mendeleev University of Chemical Technology of Russia (Х-2020-011).

Photometric determination of rhenium in mixed hydrochloric-nitric acidic solutions formed upon processing of molibdenite concentrate

The results of spectrophotometric study of the system Re (VII) – HNO 3 – HCl – mercaptoacetic acid – Sn (II) are used to develop a sensitive and selective method of photocolorimetric determination of rhenium in acid nitrate-sulfate solutions formed upon decomposition of molybdenite concentrates with nitric acid and also to reveal trends in complexation of aliovalent rhenium with organic sulfur ligands. Ammonium perrhenate (AR-0) was purified on a Purolite C-100 cation exchanger. Solutions of mercaptoacetic (thioglycolic) acid were prepared from chemically pure Apolda chemical (Germany). Light absorption spectra were recorded on EPS-3T (Hitachi, Japan) and Specord M-40 (Carl Zeiss Jena, Germany) spectrophotometers; the optical density of the solutions was recorded on a KFK-2 (Russia) photocolorimeter. Optimal conditions for the formation of a colored complex compound with mercaptoacetic acid in a mixed hydrochloric-nitric acid solution were determined along with the composition and stability of the complex. The mechanism of redox reactions that occur during complexation is proposed. A technique for monitoring the rhenium content in the products of hydrometallurgical processing of molybdenite concentrates is developed. The procedure provides rhenium determination in the presence of accompanying elements (Mo, Cu, Fe, Ni, etc.) and oxidizing agents (>120 g/liter The developed procedure includes preliminary separation of molybdenum and other interfering impurities by selective sorption of ions on a strongly basic anionite (ChFO) followed by their desorption with a 5 M HNO 3 solution and subsequent photocolorimetric determination of rhenium in the eluate in the form of an orange-yellow (λ max = 460 nm) mixes-ligand complex of Re (III) of assumed composition [Re(L) 3 NOCl]–, where L — is mercaptoacetic acid anion. The developed method of rhenium determination was used in analysis of effluents of washing sulfuric acid taken from the sulfuric acid workshop of the copper smelting plant of Almalyk MMC JSC (Uzbekistan).

Determination of Rhenium in Geological Samples by Isotope Dilution–Multicollector–Inductively Coupled Plasma-Mass Spectrometry with Novel Chromatographic Separation

ABSTRACTA method was developed to determine rhenium contents in geological samples using multicollector–inductively coupled plasma-mass spectrometry (MC–ICP-MS) and extraction with an ion-exchange resin. Samples were digested in Carius tubes and osmium was converted into volatile OsO4, which was purified by distillation and microdistillation. The purified Os contents and isotopic ratios were determined using negative thermal ionization mass spectrometry. After the distillation of Os, the samples were treated with HF, then 1.2 M HCl, and loaded on ion-exchange resin columns. Re was eluted using 0.75 M HNO3 and directly determined by MC–ICP-MS. This method was validated using a series of reference materials and the analytical Re data are consistent with the literature values. This method precision (relative standard deviation) ranged from 0.8 to 6%. The procedural blank and detection limit (3σ) of Re were 1.1 pg and 0.5 pg/g (for a sample size of 2g), respectively. These results indicate that the proposed method can be applied to determine trace Re in geological samples. Using Carius tube digestion combined with HF desilicification and redissolution, the Re and Os contents found in the soluble and insoluble phases of several reference materials indicated that the distributions of Re and Os were homogeneous and heterogeneous, respectively.

Application of high-resolution 40.68 MHz radial-viewing inductively coupled plasma optical emission spectrometry in rhenium determination

The possibilities of 40.68 MHz radial-viewing inductively coupled plasma optical emission spectrometry equipped with a high-resolution spectrometer (spectral bandwidth = 5 pm) (HR-ICP-OES) were studied in the determination of rhenium in molybdenum and copper concentrates. By using equipment with a high spectral resolution, a hyperfine structure (HFS) of the most prominent lines of rhenium (i.e., Re II 197.248 nm, Re II 221.426 nm and Re II 227.525 nm) were registered. The HFS components, under high-resolution conditions, were used as separate prominent lines in order to circumvent spectral interferences in the presence of complex matrix containing Mo, Al, Ti, Fe, Mg, Ca and Cu. The Q-concept was applied for quantification of the spectral interferences and optimum line selection. Microwave acid digestion method was used as a sample dissolution procedure. The feasibility, accuracy and precision of the analytical results were experimentally demonstrated by certified reference materials from molybdenum and copper concentrates. Comparative data for true detection limits by using HR-ICP-OES 40.68 MHz ICP and Slurry sampling total reflection X-RAY fluorescence were presented in the determination of rhenium in CRM Molybdenum concentrate “CGL-202”.

Determination of Rhenium in Seawater from the Jiulong River Estuary and Taiwan Strait, China by Automated Flow Injection Inductively Coupled Plasma–Mass Spectrometry

ABSTRACTA novel and automated flow injection (FI) system using a commercially available anion-exchange resin was developed for the online determination of rhenium in seawater by inductively coupled plasma–mass spectrometry (ICP–MS). The flow rate, reagent concentration, and sample volume were optimized. The rhenium concentration was determined using the integrated peak area through interpolation of standard addition calibration curves. The relative standard deviation was less than 2.45% (n = 5), the recoveries were from 94.59 to 104.11%, and the linear dynamic range of the method was up to 998 ng kg−1. There was a good agreement between the rhenium concentrations in a standard measured in this work with results from previous studies. The limit of detection was 0.11 ng kg−1 for a sample volume of 7.5 mL and one cycle required 8.33 min. The developed FI–ICP–MS method was used to determine rhenium in seawater from the Jiulong River Estuary and Taiwan Strait.

Spectral interferences in the determination of rhenium in molybdenum and copper concentrates by inductively coupled plasma optical emission spectrometry (ICP-OES)

This paper deals with spectral interferences of complex matrix containing Mo, Al, Ti, Fe, Mg, Ca and Cu in the determination of rhenium in molybdenum and copper concentrates by inductively coupled plasma optical emission spectrometry (ICP-OES). By radial viewing 40.68MHz ICP equipped with a high resolution spectrometer (spectral bandwidth=5 pm) the hyperfine structure (HFS) of the most prominent lines of rhenium (Re II 197.248nm, Re II 221.426nm and Re II 227.525nm) was registered. The HFS components under high resolution conditions were used as separate prominent line in order to circumvent spectral interferences. The Q-concept was applied for quantification of spectral interferences.The quantitative databases for the type and the magnitude of the spectral interferences in the presence of above mentioned matrix constituents were obtained by using a radial viewing 40.68MHz ICP with high resolution and an axial viewing 27.12MHz ICP with middle resolution. The data for the both ICP-OES systems were collected chiefly with a view to spectrochemical analysis for comparing the magnitude of line and wing (background) spectral interference and the true detection limits with spectroscopic apparatus with different spectral resolution.The sample pretreatment methods by sintering with magnesium oxide and oxidizing agents as well as a microwave acid digestion were applied.The feasibility, accuracy and precision of the analytical results were experimentally demonstrated by certified reference materials.

Determination of rhenium and osmium by ICP-MS for galena and sphalerite

Digestion with aqua regia in a Carius tube and separation of Re with anion exchange resin is commonly employed for Re–Os dating of molybdenite and pyrite. However, the recovery of Re is extremely low when this routine anion exchange method is applied to galena, causing difficulty in Re–Os dating of galena. In this study, we investigated the mechanism of Re loss during sample preparation and tested a revised procedure for Re–Os dating of galena and sphalerite.

The Rhenium Determination in Copper and Molybdenum Ores and Concentrates by ICP Atomic Emission Spectrometry

The ICP-AES technique was developed for rhenium determination in the range of 0.00002 - 0.05 % in copper and molybdenum ores along with their concentrates. The sample pretreatment method by sintering with magnesium oxide and oxidizing agents was offered for analysis; optimum conditions for samples digestion were established. These conditions enabled to pass rhenium into solution with no losses. Matrix influence on rhenium emission spectral lines was studied and methods were investigated to eliminate matrix effects. The analysis results of rhenium-containing ores and concentrates certificated reference materials and mixtures on their basis, obtained by the developed procedure, agreed well with the certified rhenium content values. Keywords: Rhenium, inductively coupled plasma atomic emission spectral analysis, internal standard, sintering, copper and molybdenum concentrates and ores.

Determination of rhenium and osmium complexes by surface-assisted laser desorption/ionization coupled to Orbitrap mass analyzer

A surface-assisted laser desorption/ionization (SALDI) source is coupled to the Orbitrap mass analyzer; the instrumental approach is tested for the analysis of rhenium (Re) and osmium (Os) complexes with 8-mercaptoquinoline. Silicon (Si) material obtained by laser treatment of monocrystalline Si is used as SALDI substrate. All studied complexes are detected as radical cations, with no protonated molecules. The comparison of SALDI, matrix-assisted laser desorption/ionization (MALDI), and direct laser desorption/ionization (LDI) on metal plates in the same instrumental setup demonstrated that the detection of the studied complexes using SALDI provides the highest sensitivity. The ability to analyze samples rapidly, high purity of spectra, and good analytical parameters make SALDI coupled to the Orbitrap mass analyzer a potentially powerful tool for the detection of Re and Os complexes and related organic, UV-absorbing compounds.

The Design of Re‐usable Carius Tubes for the Determination of Rhenium, Osmium and Platinum‐Group Elements in Geological Samples

The traditional Carius tube technique is cumbersome and requires skilful work to seal the Carius tube, which can be used only once. We describe a modification to the technique that does not require the use of a high‐temperature welding torch to melt the Carius tube to seal it. The newly designed Carius tube consists of a main body with a 3 mm‐thick glass wall, a neck and head with walls 4 mm in thickness, and an efficient screw‐thread stopper. These new features allowed the tube to be used repeatedly. We demonstrate relatively low procedural blanks derived for Re and Os, and platinum‐group elements (PGEs), using the redesigned tube. A temperature of 220 °C could be reached for about 5 ml of HNO3 for a 47 ml tube and for 32 ml of inverse aqua regia for a 200 ml tube. This digestion technique can be used for routine analysis of Re and PGEs in geological samples.

Up-to-date methods for the determination of rhenium

We present a review of literature on the methods for rhenium determination published from 2000 to 2010.

Atomic-Emission Determination of Rhenium in Anthropogenic Raw Materials of Steel Production

The method including microwave acidic dissolution of samples and atomic-emission analysis of rhenium for determination of rhenium in cupper-molybdenum and lead-cupper wares is proposed. The range of determination concentration of metal is 0.05 – 0.5 mass percent, standard deviation of repeatability is 0.002 – 0.01 %.

Field determination of rhenium in plants using catalytic test methods with dimethyldithiooxamide and Sulfonitrazo P

Methods for the field determination of rhenium in plants have been developed. The speciation of rhenium in solutions throughout the process of sample preparation has been investigated. It has been shown that, in the initial ethanol and water-salt extracts, rhenium occurs as perrhenate ions. Perrhenate ions have been established to be partially reduced in time to give Re(VI). Since test methods have been developed for determining rhenium as perrhenate-ions, their partial reduction in the process of sample preparation can lead to an low level of the results. The optimal conditions for preserving rhenium as perrhenate ions have been determined. Two procedures (in four versions) providing the determination of as low as 5 ng of rhenium in a 1-g sample with an error below 23% have been proposed. The developed procedures have been applied in the places of the collection of plant materials for the regional investigation of the occurrence of rhenium in the territories of different ore contents.

Determination of rhenium in gold-containing ores by X-ray fluorescence spectrometry

A procedure is developed for determining rhenium in gold-containing ores by X-ray fluorescence spectrometry. The adsorption preconcentration of perrhenate ions on activated charcoal is studied. It is found that the pH of the solution, the time of exposing the adsorbent to the solution, UV irradiation, and the presence of associate elements (tungsten, gold, silver, and copper) affect the adsorption. The procedure is applied to the X-ray fluorescence determination of rhenium in gold-containing ores from different deposits.

Determination of rhenium in manganese nodules by inductively coupled plasma mass spectrometry

Understanding of rhenium behavior in seawater gives an idea of the possible behavior of 99Tc, which is an important radionuclide in long-term dose assessment for humans. In this study, Re determinations in manganese nodules, which have high Mn content, were carried out. Since Mn, Tc and Re are the member of group 7A in the periodic table, accumulation of Tc and Re in the nodules was also expected. After alkaline fusions and chemical separations, Re concentrations in manganese nodules were measured by ICP-MS. Total chemical recovery of the method for Re was 95% and the detection limit was 4.5 ng/kg. Re concentrations in the manganese nodules were very low, <4.5–49 ng/kg. The results indicated that the nodules had been mineralized under oxic conditions. This type of nodule could not be an important geochemical reservoir of Re and 99Tc in the sea.

Determination of rhenium in mineral raw materials by stripping voltammetry

The studies on the electropreconcentration of ReO 4 − from 1 M HNO3 solutions have shown that, at −0.8 V, ReO 4 − is reduced to ReO2 and Re0 at the surface of an impregnated graphite electrode. Two anodic peaks were observed in the voltammogram of the electrooxidation of the deposit obtained. The conditions for the adsorption isolation of ReO 4 − on activated carbon from a complex matrix containing Mo(VI), W(VI), Cu(II), Ag(I), and Au(III) were selected. To intensify the adsorption, the solutions are irradiated with UV. A procedure for determining rhenium in mineral ores and naturally occurring samples was proposed.

Advanced liquid and solid extraction procedures for ultratrace determination of rhenium by radiochemical neutron activation analysis

Radiochemical neutron activation analysis (RNAA) procedures for determination of Re at the ultratrace level based on use of liquid-liquid extraction (LLE) and extraction chromatography (EXC) have been developed. Two different LLE procedures were used depending on the way of sample decomposition using either 2-butanone or tetraphenylarsonium chloride in CHCl3. EXC employed new solid extractant materials prepared by incorporation of the liquid trioctyl-methylammonium chloride into an inert polyacrylonitrile matrix. The RNAA procedures presented have been compared and applied for Re determination in several biological and environmental reference materials.

Development of a radiochemical neutron activation analysis procedure for determination of rhenium in biological and environmental samples at ultratrace level

Radiochemical neutron activation procedures using liquid-liquid extraction with tetraphenylarsonium chloride in chloroform from 1M HCl and solid extraction with ALIQUAT 336 incorporated in a polyacrylonitrile binding matrix from 0.1M HCl were developed for accurate determination of rhenium in biological and environmental samples at the sub-ng . g-1 level. Concentrations of Re in the range of 0.1 to 2.4 ng . g-1 were determined in several botanical reference materials (RM), while in a RM of road dust a value of ~10 ng . g-1 was found. Significantly elevated values of Re, up to 90 ng . g-1 were found in seaweed (brown algae). Results for Re in the brown algae Fucus vesiculosus in which elevated 99Tc values had previously been determined suggested possible competition between Re and Tc in the accumulation process.