火焰原子吸收法测定铅锌矿中微量镓

将样品中的硫化物用HNO3氧化为硫酸盐后，再用HNO3、HF、H2SO4进一步溶解，在6mol/LHCl介质中用乙酸丁酯萃取镓，水反萃取后，用火焰析子吸收法测定Ga，该法检出限为0．80μg/mL，相对标准偏差为2．1％，用该法测得国家一级标准品的结果均与推荐值相符。     

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 arsenic and zinc in tin oxide by X-ray fluorescence

Summary An XRF method to determine arsenic and zinc in high-purity tin oxide in the range of 10–1,000 ppm is described. The sample is pressed as a double-layer pellet and the analysis is carried out by using Philips PW-1220 X-ray spectrometer. Limits of detection are 13 ppm (As) and 8 ppm (Zn). Accuracy is better than 10% at a level of 50ppm; standard deviations are 8 and 9 % at this level.

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Bestimmung von Arsen und Zink in Zinnoxid mit Hilfe der Röntgenfluorescenz

Zusammenfassung Das beschriebene Verfahren eignet sich zur As- und Zn-Bestimmung im Bereich von 10 ppm–1000 ppm in Zinnoxid. Die Probe wird zu einer Doppelschichttablette gepreßt und die Analyse mit Hilfe eines Philips PW-1220 Röntgenspektrometers durchgeführt. Die Erfassungsgrenzen sind 13 ppm (As) bzw. 8 ppm (Zn). Die Genauigkeit ist besser als 10 % (50 ppm-Bereich); die Standardabweichung in diesem Bereich beträgt 8 bzw. 9 %.

     

Determination of copper,gallium and zinc in “standard rocks” by neutron activation

A neutron activation method for the simultaneous determination of copper, gallium and zinc in rocks is described. The method is based on anion-exchange separation steps and measurement of γ-activity. Chemical yields were determined by re-activation. Results for a series of igneous “standard rocks” are presented. The accuracy of the mean values is ca. 5% for concentrations exceeding 10 p.p.m.     

Column selection and optimization for sulfur compound analyses by gas chromatography

The analysis of sulfur-containing compounds using fused silica capillary columns and the Sulfur Chemiluminescence Detector has been investigated. This combination of an inert chromatographic system and a high sensitivity, selective detector provides significant advantages for the analysis of low levels of sulfur compounds in complex matrices over existing techniques. Capillary columns coated with thick films (1–4 μm) of methyl silicone stationary phase permit separation of most sulfur containing compounds and, when used with sub-ambient column temperatures, these columns can be used for the separation of sulfur gases. The effects of stationary film thickness, column length, and internal diameter for the measurement of sulfur compounds in hydrocarbon matrices has been determined.     

Structure analysis and photocatalytic properties of spinel zinc gallium oxonitrides

This report describes a detailed structural, electronic, and catalytic characterization of zinc gallium oxonitride photocatalysts with a spinel crystal structure. The bandgap decreases to less than 3 eV with increasing nitrogen content (<3 wt%) and these photocatalysts are active in visible light (λ>420 nm) for the degradation of cresol and rhodamine B. Density functional theory calculations show that this bandgap reduction is in part associated with hybridization between the dopant N 2p states and Zn 3d orbitals at the top of the valence band. X-ray photoelectron measurements indicate that nitrogen is indeed interacting with the oxide precursor through the formation of both nitride- and oxonitride-type species. The incorporation of nitrogen reduces the uniformity of the local structure of the spinel Zn-Ga-O-N (ZGON) species, as reflected in X-ray absorption spectra and Raman measurements relative to zinc gallate, which suggests the presence of defects. The oxonitrides exhibit faster photocatalytic rates of reaction than the oxide precursor. The degradation mechanisms were determined to be via the attack by hydroxyl radicals and holes for rhodamine B and cresol, respectively. Addition of Pt as a co-catalyst increased the rate of photodegradation, a result attributed to better charge separation.     

Regioselective (site-selective) functionalization of unsaturated halogenated nitrogen, oxygen and sulfur heterocycles by Pd-catalysed cross-couplings and direct arylation processes

This tutorial review focuses on several practical synthetic transformations utilising palladium catalysis that facilitate the synthesis of functionalized unsaturated heterocycles in a regioselective (site-selective) manner. Cross-couplings of electron-deficient, electron-neutral and electron-rich unsaturated halogenated heterocycles with various organometallic reagents, and other types of nucleophiles, are detailed. Direct arylation of electron-rich unsaturated heterocyclic compounds by C-H functionalization is also presented.     

The synthesis and characterization of aluminum,gallium and zinc formamidinates

Reactions of the formamidinate ligand, RN(H)C(H)NR, L^H, (R = 2,6-diisopropylphenyl), with AlMe₃, AlMe₂Cl, GaMe₃ and ZnEt₂ were investigated to examine potential coordination modes of the ligand and the effect of hydrolysis on the products. Nine new complexes have been fully characterized by X-ray crystallography and other spectroscopic techniques and highlight the diverse coordination modes of the formamidinate ligand.     

Trifluorovinyl derivatives of zinc and tin in the synthesis of trifluorostyrenes

Conclusions A method of obtaining trifluorostyrene and its derivatives (p-Me, p-MeO, p-Cl) has been developed by the cross combination reaction of aryl iodides with trifluorovinylzinc chloride catalyzed by palladium complexes. In the case of aryl iodides with strong electron accepting substitutents a stable palladium complex was formed which did not react in the cross combination reaction. Under more drastic conditions it is possible to use trifluorovinyltrialkylstannanes in place of the organozinc compounds.Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1647–1649, July, 1985.     

Thermodynamic study of the system cadmium - zinc,cadmium - lead,cadmium - tin,bismuth - cadmium,tin - zinc,and lead - tin

Russian Chemical Bulletin -     

Calorimetric study of the adsorption of air pollutants on alumina-supported tin and gallium oxides

The differential enthalpies of adsorption of air pollutants such as SO₂, NO₂, NO on aluminasupported tin and gallium oxides were measured by calorimetry coupled with isothermal volumetry. Whatever the amount of tin or gallium on alumina, the enthalpies of adsorption of SO₂ at low coverage were of the same order of magnitude or up to 50 kJ/mol lower than those of the support. The amount of SO₂ adsorbed decreased with increasing SnO₂ loading and increased with increasing Ga₂O₃ loading on the alumina. The differential enthalpies of adsorption of NO₂ are close to those on the support whatever the amount of tin or gallium (around 120–130 kJ/mol). NO is only reversibly adsorbed on the samples. The calorimetric data of ammonia adsorption are given for comparison.     

Determination of the sulfur distribution in stone by electron microprobe analysis

An electron microprobe was used to determine the sulfur distribution in stone materials, especially sedimentary rocks. The investigations were performed to elucidate damage mechanisms in natural stones built in historical monuments. Quantitative results could be attained using one single calibration curve determined by synthetic standard samples. The applicability of the technique was proved by samples subjected to different exposure simulation experiments.     

Selective tin and zinc mediated allylations of carbonyl compounds in aqueous media

Aldehydes undergo preferential allylation in the presence of ketones by the tin or zinc mediated method, easily effected in aqueous media.     

Efficient synthesis of diorganyl selenides via cleavage of Se-Se bond of diselenides by indium(III) catalyst and zinc

A simple and efficient procedure for the synthesis of unsymmetrical diorganyl selenides from an one-pot indium(III) catalyzed procedure, in the presence of zinc, has been developed. Various organic halides and even the unreactive organic chlorides underwent the reaction efficiently. Also diaryl and dialkyl diselenides underwent the coupling reaction.     

Determination of zinc in gallium arsenide by electrothermal atomic absorption spectrometry with the L''vov platform and matrix modification

Summary A method is described for the determination of zinc in gallium arsenide by ETAAS with platform atomization and matrix modification. The sample is decomposed with nitric and hydrochloric acids, ortho-phosphoric acid is added as a matrix modifier and the diluted solution is injected into the furnace. The optical correction of the nonspecific absorbance is readily achieved by means of a conventional deuterium lamp. Platform atomization improves the peak repeatability by a factor often in comparison with wall atomization. For a 40 mg sample, with reduced argon flow rate in the atomization step, the detection limit is 0.08 g Zn g^–1 (4×10¹⁵ atoms cm^–3). Results obtained by analysing Zn-doped GaAs samples are presented. The relative standard deviation of the overall procedure is 4–8%.

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Bestimmung von Zink in Galliumarsenid durch ETAAS mit L'vov-Plattform und Matrixmodifizierung

     

焦炭中硫的空间分布规律研究

采用炼焦混合煤模拟工业焦化过程,研究了焦炭中硫的空间分布规律。结果表明,焦炭柱同一高度的有机硫、无机硫的质量分数从中心到边缘逐渐升高;相同取样位置处裂纹表面的有机硫、无机硫比对应内部位置硫的质量分数高;对于炭化室直径为230mm的模拟实验,有机硫增加约0.035%,无机硫增加约0.08%。XPS分析显示,有机硫与无机硫的质量分数的差异是由噻吩硫及金属硫化物的质量分数不同造成的。二维相似模拟实验进一步证实焦炭柱中硫的质量分数从中心沿径向到边缘逐渐升高。