Rapid determination of indium,nickel and copper in NBS standard reference material by substoichiometric radioactivation analysis

A method of rapid determination for indium, nickel and copper in Spinach (NBS; SRM-1570) by substoichiometric radioactivation analysis is described. The method is based on the principle that an equal amount of non-irradiated test sample is added to the irradiated standard sample and subsequent substoichiometric extraction for the irradiated test and standard samples is carried out. Indium is extracted as diethyldithiocarbamate into carbon tetrachloride, nickel as dimethylglyoximate into chloroform and copper as dithizonate into carbon tetrachloride. The radioactivities of these extracts are measured by NaI(Tl) or Ge(Li) detector coupled with pulse-height analyser. The analytical results obtained by the method were in good agreement with our published values and certified values by NBS.     

Direct spectrophotometric determination of indium in tin

Indium is separated from tin by an anion-exchange process in 0.5 M hydrochloric acid solution. Subsequently, the indium is extracted into 1,2-dichlorobenzene as its complex with 5,7-dichloro-8-quinolinol. The complex forms and extracts quantitatively in the pH range 3–7. The yellow, organic phase is measured spectrophotometrically at 415 mμ; ; its absorbancy is directly proportional to the indium content of the aqueous phase up to a total of 1.5 mg of indium per 50 ml. This procedure quantitatively separates the two metals, allows one to determine the indium content of indium(<5%)-tin alloys with a relative error less than 0.7%, and considerably reduces color fading errors inherent in some previously reported spectrophotometric methods for indium.     

Substoichiometric determination of trace impurities in high-purity materials by radioactivation analysis

The substoichiometric determination of some impurities in gallium arsenide and selenium supplied by OEC and IUPAC, respectively, as reference materials for radioactivation analysis is described.     

Determination of micro-amounts of indium in zinc and in gallium by radioactivation

Summary A method was developed to determine micro-amounts of indium in zinc and in gallium by radioactivation analysis, using 1 g Ra-Be as thermalneutron source. By activation of an amount of 10 g metallic zinc during 5 hours and counting the activity in a well-type NaI-scintillation counter, 17.4 counts per sec. per 10 g Zn were obtained. This activity is practically entirely due to the 13.8 h.⁶⁹Zn, the 52-mn isotope being a pure-emitter.By activation of indium in the same conditions the¹¹⁶In, 54-mn isotope, gives a counting rate of 28.9 counts per second per 10 mg metal, so that it was possible to determine amounts of indium in zinc, using 10 g samples varying from 0.004% to 0.16% with a mean error of 2.3%, without chemical separation. To determine trace amounts of Indium in Gallium by activation at the same conditions as described above, it was necessary to carry out a chemical separation. 1 g metallic Ga gave indeed rise to an activity of 115 counts per second, mainly due to the 14.1-h.⁷²Ga. The activation of the Ga-In samples was therefore carried out in an aqueous solution of their sulfates. After activation, potassium iodide and sulfuric acid were added as to obtain a 2 M solution of HI. The indium iodide was then extracted with diethyl ether and the ethereal solution introduced in a vial fitting the well-type crystal. Using 0.5-g Ga samples it was possible to determine indium amounts down to 0.2 mg, with a mean error of about 5%.

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Zusammenfassung Eine Methode zur Bestimmung kleiner Mengen Indium in Zink und in Gallium durch Aktivierungsanalyse wurde unter Verbindung von 1 g Ra-Be als thermische Neutronenquelle entwickelt. Nach Aktivierung von 10 g metallischem Zink durch 5 Stunden und Bestimmung der Aktivität in einem becherförmigen NaJ-Szintillationszähler wurden 17,4 Stöße pro Sekunde pro 10 g Zn beobachtet. Diese Aktivität kommt praktisch völlig dem⁶⁹Zn von der Halbwertszeit 13,8 Stunden zu, da das Isotop mit der Halbwertszeit 52 Minuten ein reiner-Strahler ist.Durch Aktivierung von Indium unter den gleichen Bedingungen gibt¹¹⁶In mit der Halbwertszeit 54 Minuten 28,9 Stöße pro Sekunde für 10 mg Metall, so daß es möglich war, unter Verwendung von 10 g Zink Indiummengen zwischen 0,004% und 0,16% mit einem mittleren Fehler von 2,3% ohne vorhergehende chemische Trennung darin zu bestimmen. Zur Bestimmung von Indiumspuren in Gallium durch Aktivierung unter den gleichen Bedingungen war es notwendig, eine chemische Trennungsmethode auszuarbeiten. 1 g metallisches Gallium zeigte tatsächlich einen Anstieg der Aktivität auf 115 Stöße pro Sekunde pro 1 g, die vor allem dem⁷²Ga der Halbwertszeit 14,1 Stunden zukommt. Die Aktivierung der Ga-In-Proben wurde daher in einer wäßrigen Lösung ihrer Sulfate durchgeführt. Nach der Aktivierung wurde Kaliumjodid und Schwefelsäure bis zu 2-m Konzentration an Jodwasserstoff zugesetzt. Das Indiumjodid wurde dann mit Diäthyläther extrahiert und die ätherische Lösung in eine dem becherförmigen Kristall angepaßte Schale gebracht. Unter Verwendung von 0,5 g Gallium war es möglich, Indiummengen bis herab zu 0,2 mg mit einem mittleren Fehler von etwa 5% zu bestimmen.

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Résumé On a mis au point une méthode de microdosage de 1'indium dans le zinc et le gallium par radioactivation à l'aide d'une source de neutrons thermiques de 1 g de Ra-Be. Après irradiation de 10 g de zinc métallique pendant 5 heures, on a compté 17,4 coups par seconde lors de la mesure de l'activité dans un compteur à scintillations à cristal creux d'iodure de sodium. Pratiquement, cette activité est entièrement due au⁶⁹Zn de période 13,8 h, son isotope de période 52 mn étant un émetteur-pur.Lorsqu'on active l'indium dans les mêmes conditions, l'isotope¹¹⁶In de période 54 mn donne au compteur 28.9 coups par seconde pour 10 mg de métal de sorte qu'il est possible de déterminer la teneur en indium du zinc sur des échantillons de 10 g pour des valeurs variant de 0,004% à 0 16%, avec une erreur moyenne de 2,3% et sans séparation chimique. Pour effectuer le dosage de traces d'indium dans le gallium par application de la même méthode d'activation, il est nécessaire d'effectuer une séparation chimique. 1 g de gallium métallique donne en effet naissance à une activité de 115 coups par seconde qui sont principalement dûs à l'isotope⁷²Ga de période 14,1 h. En conséquence, l'activation des échantillons de Ga-In a été effectuée dans une solution aqueuse des sulfates de ces métaux. Après activation, on ajoute de l'iodure de potassium et de l'acide sulfurique de façon à obtenir une solution 2 M d'acide iodhydrique. L'iodure d'indium est alors extrait dans l'éther diéthylique et la solution éthérée est introduite dans une fiole s'ajustant dans le cristal creux. En employant des échantillons de gallium de 0,5 g, il a été possible de déterminer des quantités d'indium de 0,2 mg avec une erreur moyenne d'environ 5%.

     

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.     

Vibrational analysis of oxygen-plasma treated indium tin oxide

High-resolution electron-energy-loss spectroscopy (HREELS) showed that the dominant feature in the HREELS spectrum of the ‘as-received’ ITO was the loss peaks associated with the CH_x group. Oxygen-plasma treatment of ITO led to the disappearance of the CH_x loss peaks, and a concomitant increase in the intensity of the phonon peaks at 71 and 134 meV. The result indicates the removal of the CH_x group and additional oxidation of the ITO surface by the oxygen-plasma treatment. Both processes are proposed to be responsible for the increase in work function of ITO by the oxygen-plasma treatment.     

Determination of indium,copper and nickel in glassmaking materials and NBS standard reference materials by substoichiometric radioactivation analysis

The paper describes a method of radioactivation analysis for the determination of indium, copper and nickel. In the determination of indium, ordinary and displacement substoichiometries were applied for glassmaking materials while ordinary substoichiometry was applied for NBS standard reference materials. Copper and nickel in glassmaking materials and NBS standard reference materials were also determined by the displacement and ordinary substoichiometries. Indium contents in glassmaking materials by the two methods agreed with each other. The analytical results of indium, copper and nickel in NBS' SRM were also in good agreement with published values and certified values by NBS.     

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.     

Functionalization of indium tin oxide

The preparation and functionalization of ITO surfaces has been studied using primarily X-ray photoemission spectroscopy and infrared reflection-absorption spectroscopy (IRRAS) and the reagents n-hexylamine and n-octyltrimethoxysilane (OTMS). Particular attention has been paid to characterization of the surfaces both before and after functionalization. Surfaces cleaned by ultraviolet (UV)/ozone treatment and subsequently exposed to room air have approximately 0.5-0.8 monolayers (ML) of adsorbed impurity C. Most is in the form of aliphatic species, but as much as one-half is partially oxidized and consists of C-OH, C-O-C, and/or >C=O groups. The coverage of these species can be reduced by cleaning in organic solvents prior to UV/ozone treatment. The OH coverage on the ITO surfaces studied here is relatively small (approximately 1.0 OH nm-2), based on the Si coverage after reaction with OTMS. A satellite feature in the O 1s XPS spectrum, often suggested to be a quantitative measure of adsorbed OH, receives a significant contribution from sources not directly related to hydroxylated ITO. n-Hexylamine adsorbs, at a saturation coverage of approximately 0.08 ML, via a Lewis acid-base interaction. The particular acid site has not been conclusively identified, but it is speculated that surface Sn sites may be involved. For OTMS, a saturation coverage of about 0.21 ML is found, and the C/Si atom ratios suggest that some displacement of preadsorbed organic impurities occurs during adsorption. The alkyl chain of adsorbed OTMS is disordered, with no preferred stereoisomer. However, the chain appears to lie mainly parallel to the surface with the plane defined by the terminal CH3-CH2-CH2- segment oriented essentially perpendicular to the surface.     

Effect of surface modification of indium tin oxide by nanoparticles on the electrochemical determination of tryptophan

The effect of surface modification of indium tin oxide (ITO) by multi wall carbon nanotube (MWNT) and gold nanoparticles attached multi wall carbon nanotube (AuNP-MWNT) has been studied to determine tryptophan, an important and essential amino acid for humans and herbivores. A detailed comparison has been made among the voltammetric response of bare ITO, MWNT/ITO and AuNP-MWNT/ITO in respects of several essential analytical parameters viz. sensitivity, detection limit, peak current and peak potential of tryptophan. The AuNP-MWNT/ITO exhibited a well defined anodic peak at pH 7.2 at a potential of ∼669 mV for the oxidation of tryptophan as compared to 760 mV at MWNT/ITO electrode. Under optimum conditions linear calibration curve was obtained over tryptophan concentration range 0.5-90.0 μM in phosphate buffer solution of pH 7.2 with detection limit and sensitivity of 0.025 μM and 0.12 μA μM⁻¹, respectively. The oxidation of tryptophan occurred in a pH dependent, 2e⁻ and 2H⁺ process and the electrode reaction followed adsorption controlled pathway. The method has been found selective and successfully implemented for the determination of tryptophan in human urine and plasma samples using standard addition method. The electrode exhibited an efficient catalytic response with good reproducibility and stability.     

锡阳极泥中铟对铋含量测定的影响

采用传统Na2EDTA滴定方式测定锡阳极泥（当铟含量大于0.2mg时）试液会出现试液颜色无明显突跃和滴定终点难以判定的现象。本文主要探讨了Na2EDTA滴定法测定锡阳极泥试样中铋含量,当铟含量大于0.2mg时,对铋量测定有影响;讨论了铟在三种滴定条件下的络合行为;优化了铋的滴定条件;论证了在10.00mg、20.00mg、30.00mg、40.00mg铋标准溶液中加入不同含量的铟标准溶液,并在实际锡阳极泥样品YTXN-7中加入不同含量的铟,探讨了两种计算方法。实验表明,通过调节试液pH=1.5～1.7,采用Na2EDTA标准滴定溶液滴定至试液红色刚消失,加热试液至70℃～80℃,继续滴定,能够出现完成铋铟的络合滴定;当铟量在1.00mg～2.00mg时,方法2的实验数据更理想。     

Trace determination of iron,cobalt, nickel and copper in zirconium fluoride by substoichiometric radioactivation analysis

Trace amounts of transition elements (Fe, Co, Ni and Cu) in zirconium fluoride and NBS SRM's were determined by substoichiometric radioactivation analysis. The contents of impurities in sublimed sample were less than those of high-purity material and of reagent grade. The detection limits of these elements in zirconium fluoride were 10 ng/g for iron, 0.01 ng/g for cobalt, 1 ng/g for nickel and 0.1 ng/g for copper. The analytical results for iron, cobalt, nickel and copper in NBS SRM's were in good agreement with certified values.     

电位溶出分析法同时测定锡, 铅, 铜

本文应用电位溶出分析法进行同时测定锡、铅和铜的研究。结果发现在草酸溶液中锡、铅和铜有分离清晰的平台,其溶出讯号与浓度呈线性关系,可用于定量分析。用这一方法测定了某些罐头食品中痕量锡、铅和铜,获得满意的结果。     

Substoichiometric radioactivation analysis for ytterbium

The substoichiometric separation of Yb(III) can be achieved by the extraction of a substoichiometric amount of thenoyltrifluoroacetone and an excess amount of phenanthroline in benzene. The appropriate pH range for the substoichiometric extraction is 6–8. The reproducibility of the substoichiometric extraction of Yb(III) is very good as RSD 1%. As an example, Yb in a manganese nodule is determined by the substoichiometry combined with the radioactivation analysis. The content of Yb is 17.63±0.23 g/g. The present procedure can be applied to the determination of other rare earth elements.     

An oscillopolarographic method for the rapid simultaneous determination of tin and indium in their alloys

Summary A simple polarographic method is drescribed for the simultaneous determination of Sn and In in their alloys. A solution of 4N NH₄Cl and 0. 2 N HCl was chosen as base electrolyte. The coefficient of variation of the analysis is smaller than 1% for In and smaller than 2% for Sn. Sn is determined by reduction, In by stripping.

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Zusammenfassung Eine einfache polarographische Methode wird beschrieben, die eine gleichzeitige Bestimmung von Sn und In in ihren Legierungen ermöglicht. Grundelektrolyt ist eine Lösung, die 4n an NH₄Cl und 0,2n an HCl ist. Der Variationskoeffizient der Analyse ist für Indium kleiner als 1%, für Zinn kleiner als 2%. Sn bestimmt man durch Reduktion, In durch Amalgampolarographie (stripping).

     

The electroreduction of formaldehyde on tin and indium

The electrochemical behavior of formaldehyde on tin and indium cathodes has been studied over a wide range of pH (0.4–13), concentrations (1×10^?3 to 6×10^?1M) and potentials. Potentiostatic, potentiodynamic, ac impedance and photoe mission techniques were used to determine the kinetics of the reaction and to postulate a mechanism. The behavior on indium is similar to that reported on mercury cathodes. Tafel slopes are about 65 to 80 mV/decade. This value indicates that protonation of a reaction intermediate is the rate determining step of the reaction. The value of the slope depends slightly on concentration and pH because of adsorption under Temkin conditions. The reaction order with respect to formaldehyde is close to 1 in the limiting current region, but smaller in the Tafel region. The effect of formaldehyde on tin in neutral and alkaline solutions is to decrease the hydrogen overpotential by about 0.5 V, without affecting the Tafel slope. The rate of formaldehyde reduction is very slow. An explanation for this catalytic effect is postulated, based on the adsorption of formaldehyde-related species on the electrode surface. Formation of bridge-type complexes is also postulated. The exact nature of the adsorbed species is unknown. Preliminary results indicate that the behavior of formaldehyde on lead is similar to that on tin. The influence of this species on the reduction of formic acid on tin and lead is discussed.     

Highly conducting and transparent sprayed indium tin oxide

Spray pyrolysis process has been used to deposit highly transparent and conducting films of tin doped indium oxide onto glass substrates. The electrical, optical and structural properties have been investigated as a function of various deposition parameters namely dopant concentrations, temperature and nature of substrates. X-ray diffraction patterns have shown that deposited films are polycrystalline without second phases and have preferred orientation [400]. Indium tin oxide layers with small resistivity value around 7.10⁻⁵Ω.cm and transmission coefficient in the visible and near IR range of about 85–90 % have been easily obtained.