Subtoichiometric determination of indium and tin by radioactivation analysis

A method of radioactivation analysis has been developed for the determination of indium and tin. It is based on substoichiometric extraction of indium diethyldithiocarbamate into carbon tetrachloride from a slightly ammoniacal solution in the presence of potassium cyanide. With this method, indium can be determined via^116m In (T=54 min) and tin via^113m In (T=104 min) which is formed by the reaction¹¹²Sn(n, ψ)¹¹³Sn. The method has been applied to the determination of indium in metallic zinc and of tin in tin-doped gallium arsenide, and 0.4 ppb of indium was analyzed in a zinc sample.     

The determination of tin in biological samples

A rapid method is described for the determination of tin in biological material, using¹²³Sn (T=40 m). The chemical procedure is based on the nearly quantitative extraction of tetravalent tin into toluene from an acid 1.3M iodide solution. The recovery is determined by spiking the solution with¹¹³Sn and measuring the activity of the^113mIn daughter in the counting sample. The lower limit of the determination is ?0.01μg. Results are given for standard kale powder and dried animal blood.     

Determination of indium in metallic tin and cadmium by substoichiometric neutron activation analysis

The paper deseribes the determination of indium in metallic tin and cadmium metals by the direct method, which is a variant of substoichiometric radioactivation analysis. It is based on substoichiometric extraction of indium diethyldithiocarbamate into carbon tetrachloride. Indium in tin metal was determined by^116mIn (T=54 min), while^115mIn (T=4.5 h), formed by the reaction¹¹⁴Cd(n, γ)¹¹⁵Cd was used for cadmium samples. The irradiated sample was dissolved and the radioactivity of^116mIn or^115mIn, A, was measured. After the separation of indium from the matrix, a known amount of indium, m, was separated substoichiometrically and the radioactivity, a, was measured. Indium was calculated as M_x=m A/a. If a known amount of the element, M, is added to the irradiated sample in advance, the equation for calculation is given as M_x-m A/a−M. By this method, indium can be determined without any consideration of self-shielding and secondary nuclear reaction of the matrix.     

Interferences in the determination of trace elements in high-purity tin

Reactor neutron activation analysis of antimony, indium and cadmium in high-purity tin is interfered with by nuclear reactions on the tin matrix. For a number of interfering reactions the cross-sections were determined. The following results were obtained:¹²²Sn(n,γ)^123mSn:σ_th=0.145 barn, I=0.79 barn;¹²²Sn(n,γ)¹¹³Sn:σ_th=0.52, I=25.4 barn;¹¹²Sn(n, 2n)¹¹¹Sn: microbarn;¹¹⁸Sn(n, α)¹¹⁵Cd: microbarn; and¹¹⁴Sn(n, p)^114m1In: microbarn.     

Fast determination of the tin content in cassiterite ores by photon activation method

Photon activation analysis has been success-fully applied to the fast and non-destructive analysis of tin in cassiterite ores based on the 159.7 keV gamma line of^123mSn produced in the¹²⁴Sn/γ, n/^123mSn reaction. In order to improve the accuracy of analytical results, corrections for self-absorption and pile-up effects were performed. Under typical conditions /15 μA electron beam current, 15 MeV bremsstrahlung energy, 5 min irradiation time and 10 min measurement/ the sensitivity of the analysis is 10 ppm. The proposed method can be used for routine analysis of tin in geological samples.     

Determination of organotin compounds by headspace solid-phase microextraction–gas chromatography–pulsed flame-photometric detection (HS-SPME–GC–PFPD)

A method based on Headspace solid-phase microextraction (HS-SPME, with a 100 μm PDMS-fiber) in combination with gas-chromatography and pulsed flame-photometric detection (GC-PFPD) has been investigated for simultaneous determination of eight organotin compounds. Monobutyltin (MBT), dibutyltin (DBT), tributyltin (TBT), monophenyltin (MPhT), and the semi-volatile diphenyltin (DPhT), triphenyltin (TPhT), monooctyltin (MOcT), and dioctyltin (DOcT) were determined after derivatization with sodium tetraethylborate. The conditions used for the extraction and preconcentration step were optimised by experimental design methodology. Tripropyltin (TPrT) and diheptyltin (DHepT) were used as internal standards for quantification of volatile and semi-volatile organotin compounds, respectively. The analytical precision (RSD) for ten successive injections of a standard mixture containing all the organic tin compounds ranged between 2 and 11%. The limits of detection for all the organotin compounds were sub ng (Sn) L⁻¹ in water and close to ng (Sn) kg⁻¹ in sediments. The accuracy of the method was evaluated by analysis of two certified reference material (CRM) sediment samples. The HS-SPME–GC–PFPD was then applied to the analysis of three harbour sediment samples. The results showed that headspace SPME is an attractive tool for analysis of organotin compounds in solid environmental matrices.     

Study of isotope exchange reactions by double labelling

This paper presents the method of double labelling in the study of the kinetics of homogeneous isotope exchange reactions. This method was tested by the determination of the Sn(II)−Sn(IV) exchange rate in hydrochloric acid medium. The system was labelled by the tracer^119mSn [initially in the Sn(IV) state]; when the isotope equilibrium was established, Sn(IV) was again labelled by tracer¹¹³Sn. The separation of Sn(II) and Sn(IV) in the given time of exchange was performed by the extraction of Sn(IV)-hydroxyquinolate into chloroform. The specific activities of the separated components were determined from the ratio of¹¹³Sn and^119mSn activities. The exchange rate was calculated from the time dependence of specific activities. The advantage and possibilities of the method of double labelling in the study of isotope exchange are discussed.     

Isotope dilution GC-MS routine method for the determination of butyltin compounds in water

A standard GC-MS instrument with electron impact ionisation has been used to develop a fast, simple and reliable method for the simultaneous determination of monobutyltin (MBT), dibutyltin (DBT) and tributyltin (TBT) in water samples. Isotope dilution analysis (IDA) is used for the determination of species, taking advantage of a commercially available spike solution containing a mixture of MBT, DBT and TBT enriched in ¹¹⁹Sn. Method detection limits for 100-mL samples were between 0.18 and 0.25 ng L⁻¹ for the three butyltin compounds with typical RSD between 2 and 4% at levels between 100 and 10 ng L⁻¹, respectively. Recovery of tin species in spiked samples (natural water, wastewater and seawater) was quantitative. The stability of butyltin compounds in collected seawater samples was also studied. The addition of a 1% (v/v) glacial acetic acid preserved tin species in the samples for at least 5 days at room temperature. The IDA method was finally implemented in a routine testing laboratory and it was subsequently accredited by the Spanish National Accreditation Body according to the requirements of UNE-EN ISO/IEC 17025.     

Neutron activation analysis of tin in biological materials and their ash using123Sn and125Sn

Tin has been determined in biological materials by NAA of the γ-emitting 40-min¹²³Sn and 9,7-min¹²⁵Sn isotopes at the sub-ppm level. For¹²³Sn, samples are wet-ashed after irradiation, whereas to allow fast radiochemistry for¹²⁵Sn, the samples are dry-ashed prior to the irradiation. Both separation techniques rely on selective solvent extraction of tin(IV) iodide, and NaI(TI) counting. Comparative analyses of several materials by both methods gave good agreement, indicating that tin is not lost on dry-ashing and that simple dissolution of the ash in an HCl?HI mixture is complete. Results by both techniques are presented for the standard materials Bowen's Kale and NBS Orchard Leaves, and for some other materials.     

The Stannides YNi x Sn2 ( x = 0, 0.14, 0.21, 1) – Syntheses, Structure, and 119Sn M?ssbauer Spectroscopy

The stannides YNi _x Sn₂ (x = 0, 0.14, 0.21, 1) were prepared by arc-melting of the pure elements. They were characterized through X-ray powder and single crystal data: ZrSi₂ type, space group Cmcm, a = 438.09(6), b = 1629.6(4), c = 430.34(7) pm, wR2 = 0.0607, 386 F ² values, 14 variables for YSn₂, CeNiSi₂ type, Cmcm, a = 440.6(1), b = 1640.3(1), c = 433.0(1) pm, wR2 = 0.0632, 416 F ² values, 19 variables for YNi_0.142(7)Sn₂, a = 441.0(1), b = 1646.3(1), c = 434.6(1) pm, wR2 = 0.0491, 287 F ² values, 19 variables for YNi_0.207(7)Sn₂, and LuNiSn₂ type, space group Pnma, a = 1599.3(3), b = 440.89(5), c = 1456.9(2) pm, wR2 = 0.0375, 1538 F ² values, 74 variables for YNiSn₂. The YSn₂ structure contains Sn1–Sn1 zig-zag chains (297 pm) and planar Sn2 networks (307 pm). The stannides YNi_0.142(7)Sn₂ and YNi_0.207(7)Sn₂ are nickel filled versions of YSn₂. The nickel atoms have a distorted pyramidal tin coordination with Ni–Sn distances ranging from 220 to 239 pm. New stannide YNiSn₂ adopts the LuNiSn₂ type. The nickel and tin atoms build up a complex three-dimensional [NiSn₂] network in which the yttrium atoms fill distorted pentagonal and hexagonal channels. Within the network all nickel atoms have a distorted square pyramidal tin coordination with Ni–Sn distances ranging from 247 to 276 pm. Except the Sn4 atoms which are located in a tricapped trigonal Y₆ prism, all tin atoms have between 4 and 5 tin neighbors between 297 and 350 pm. ¹¹⁹Sn M?ssbauer spectroscopic data of YNi _x Sn₂ show a decreasing isomer shift (from 2.26 to 2.11 mm/s) from YSn₂ to YNiSn₂, indicating decrease of the s electron density at the tin nuclei.     

The Stannides YNi x Sn2 ( x = 0, 0.14, 0.21, 1) – Syntheses, Structure, and 119Sn M?ssbauer Spectroscopy

Summary. The stannides YNi _x Sn₂ (x = 0, 0.14, 0.21, 1) were prepared by arc-melting of the pure elements. They were characterized through X-ray powder and single crystal data: ZrSi₂ type, space group Cmcm, a = 438.09(6), b = 1629.6(4), c = 430.34(7) pm, wR2 = 0.0607, 386 F ² values, 14 variables for YSn₂, CeNiSi₂ type, Cmcm, a = 440.6(1), b = 1640.3(1), c = 433.0(1) pm, wR2 = 0.0632, 416 F ² values, 19 variables for YNi_0.142(7)Sn₂, a = 441.0(1), b = 1646.3(1), c = 434.6(1) pm, wR2 = 0.0491, 287 F ² values, 19 variables for YNi_0.207(7)Sn₂, and LuNiSn₂ type, space group Pnma, a = 1599.3(3), b = 440.89(5), c = 1456.9(2) pm, wR2 = 0.0375, 1538 F ² values, 74 variables for YNiSn₂. The YSn₂ structure contains Sn1–Sn1 zig-zag chains (297 pm) and planar Sn2 networks (307 pm). The stannides YNi_0.142(7)Sn₂ and YNi_0.207(7)Sn₂ are nickel filled versions of YSn₂. The nickel atoms have a distorted pyramidal tin coordination with Ni–Sn distances ranging from 220 to 239 pm. New stannide YNiSn₂ adopts the LuNiSn₂ type. The nickel and tin atoms build up a complex three-dimensional [NiSn₂] network in which the yttrium atoms fill distorted pentagonal and hexagonal channels. Within the network all nickel atoms have a distorted square pyramidal tin coordination with Ni–Sn distances ranging from 247 to 276 pm. Except the Sn4 atoms which are located in a tricapped trigonal Y₆ prism, all tin atoms have between 4 and 5 tin neighbors between 297 and 350 pm. ¹¹⁹Sn M?ssbauer spectroscopic data of YNi _x Sn₂ show a decreasing isomer shift (from 2.26 to 2.11 mm/s) from YSn₂ to YNiSn₂, indicating decrease of the s electron density at the tin nuclei.     

The determination of nickel in air dust by neutron activation analysis

The determination of nickel in atmospheric aerosols, collected on filter paper, is performed by thermal neutron activation analysis using the⁶⁵Ni (T=2.56 h) isotope. Liquid-liquid extraction and anion-exchange are applied in the chemical separation. The absolute sensitivity of the method is ≌0.02 μg Ni. The relative sensitivity is 0.005 μg Ni/m³ if an air sample of about 1000 m³ is used.     

Dipole moments of compounds containing a cobalttin bond

The molecular electric dipole moments are reported for the series of tin-substituted tetracarbonyl cobalt compounds R_nY_m?nSn{Co(CO)₄}_4?m (m = 1–3; n ? m; R = alkyl, phenyl; Y = halogen). The effect of the substituents at the tin atom on the nature of the CoSn bond is established on calculating the (CO)₄CoSn group dipole moments. It is shown that the charge transfer in the CoSn bond is mainly determined by the inductive properties of the ligands attached to tin.     

Lattice temperature and hyperfine interactions of Pb1−xSnxTe (0.21 ≤ x ≤ 0.75)

Thin (<15 μm) samples of lead tin telluride, Pb_1?xSn_xTe (x = 0.21, 0.25, 0.55, and 0.75) have been studied by temperature dependent Mössbauer spectroscopy using the 23.8 keV gamma radiation of ^119mSn. The tin atom occupies a lattice site having cubic symmetry (QS = 0 ± 0.020 mm sec^?1) over the temperature range 78 ≤ T ≤ 240 K, and there is no evidence for a rhombic (low temperature) to cubic (high temperature) phase transition such as that reported for SnTe in this temperature interval. The lattice temperature as probed by the Sn atom is independent of the compositional parameter x and is similar to that reported for SnTe from Mössbauer studies and for Pb_0.63Sn_0.37Te from X-ray powder diffraction data. Radiation damage produced by 2-MeV proton irradiation to a total fluence of ～10¹⁷ cm^?2 at liquid nitrogen temperature does not have any effect on the Mössbauer parameters, possibly because the major damage is annealed at temperatures below 150 K.     

Determination of indium and tin by activation analysis using replacement substoichiometry

A new method for the determination of indium by activation analysis has been developed. It is based on the replacement of indium from indium dithizonate (in carbon tetrachloride) by a substoichiometric amount of aqueous mercury(II) solution. Preliminary steps are the extraction of indium from alkaline cyanide solution with an excess of dithizone solution and washing the extract with buffer solution. The time necessary for the separation is 10-20 min. With this method indium can be determined by using either short ((116m)In, t(1 2 ) = 54 min) or long-lived radioisotopes ((114m)In, t(1 2 = 50 d). As by the reaction (112)Sn (n, gamma)) (113)Sn (119d) --> (113)In (104 min), indium-113m is formed, which has a different gamma-spectrum from that of indium-114m, the determination of both indium and tin is possible. The proposed method has been applied to the determination of indium and tin in granite and gallium.     

Synthesis and reactivity of ω-haloalkyltin compounds

ω-Haloalkyltin trihalides, X(CH₂)_nSnX₃ (n ≧ 3; X = halogen) can readily be prepared in high yields by the direct reaction of stannous halides with α,ω-dihaloalkanes, catalysed by trialkylantimony compounds. The compounds are versatile starting materials for the synthesis of a variety of ω-functionallysubstituted organotin compounds R_3-mX_mSn(CH₂)_n Y (R = alkyl, phenyl; m = 0-3; X = Cl, Br, O; Y = Br, NMe₂, NEt₂, COOH, CHOHR, R₃Sn). ¹H-NMR spectral data for a series of such compounds are presented. The trends observed in the chemical shifts and the ¹¹⁹Sn—methyl proton coupling constants of Me_3-m Br_mSn(CH₂)_nBr (m = 0-3; n = 3-5) are discussed in terms of inductive effects. Intramolecular coordination between the ω-bromine atom and tin could not be demonstrated.     

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.     

Initiation of ethylene polymerization on organoelement cations L<Subscript>2</Subscript>MMe<Superscript>+</Superscript> (M = Ge,Sn) with intramolecular coordination bonds: a theoretical study

The initiation of ethylene polymerization on L₂MMe⁺ cations (M = Ge, Sn; L = alkoxy, alkyl, phenoxyiminate, β-diketonate) was studied by the PBE/TZ2P density functional method. It was found that ethylene insertion into the M—C bond of the L₂MMe⁺ cations is energetically favorable (ΔG ⁰ = −7.6—−13.6 kcal mol⁻¹). The calculated energy barriers to reactions lie in a wide range 39.8 to 75.6 kcal mol⁻¹. The lowest energy barriers were obtained for tin cations bearing hexa- and heptafluoroacetylacetonate substituents. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1338–1347, July, 2008.     

The determination of bromine in dry biological material by instrumental neutron activation analysis

Procedures for the determination of bromine by the reactions⁸¹Br(n, γ)⁸²Br (T=35.4 h) and⁷⁹Br(n, γ)^80mBr (T=4.4 h). In the case of⁸²Br a flat coaxial Ge(Li) crystal is used to measure the 619 keV photopeak. For^80mBr a planar Ge(Li) detector is applied to measure the 39 keV γ-ray. The agreement between the data obtained with both techniques for some Standard Reference Materials is satisfactory.     

Rapid determination of tungsten in rocks using183mW

A rapid method has been developed for the determination of tungsten, especially in rocks. The reaction¹⁸²W(n, γ)^183mW (T=5.3 sec), with a thermal neutron capture cross-section of 0.5 b was used. The samples were irradiated in the fast pneumatic system of the FRM, which is described briefly. The low-energy γ-rays of the isomer^183mW were measured by a high-resolving Ge(Li) detector. The sensitivity of the method is 0.1 mg tungsten with an accuracy of about 5%; the minimum concentration is 0.1–0.2% W in geological samples. The analysis time is 2 min per sample.