高纯二氧化锗中痕量杂质的ICP-MS法测定

建立了高纯二氧化锗中痕量杂质Mg、Al、Ni、Cu、Zn、In、Pb的ICP-MS测定方法。选择了仪器最佳工作条件,研究了锗基体对被测元素的干扰,方法回收率为94％～114％,RSD为11．1％～57％。     

Spectrophotometric extractive titrations-II Determination in gallium arsenide of the sum of metals extractable with dithizone

A procedure for the determination of the sum of metals, which are extractable with dithizone, in gallium arsenide is given. After the dissolution of the sample the impurities are extracted with several portions of 10(-4)M dithizone in carbon tetrachloride, gallium being screened by tartrate ion. The excess of the reagent is extracted into 0.1M aqueous ammonia and after stripping into carbon tetrachloride the dithizone is determined by spectrophotometric extractive titration. The effect of pH is considered. The limit of detection, based on the evaluation of twenty blanks, is 2.30 x 10(-8) mole, the equivalent of 1.50 mug of zinc.     

Spectrophotometric determination of germanium by phenylfluorone

Spectrophotometric studies on the reaction between germanium ions and phenylfluorone were discussed including the reaction condition to develop a spectrophotometric method for the determination of germanium. The absorbance was measured at 525 nm after 20 min from the moment of adding the reagent. Beer's Law is obeyed, the relative standard deviation is 2%, the senstivity of the method is 2.55 × 10⁻³ mg/cm³, and the molar absorbtivity based on germanium is 1.75 × 10³.     

Determination of zinc in titanium dioxide by potentiometric titration and cathode-ray polarography

Summary Procedures are described for the determination of zinc impurities in titanium dioxide. For large zinc contents (>0.1%) a titration method with hexacyanoferrate(II) was used, the end-point being determined potentiometrically. For lower contents (0.1 ppm) zinc was determined by cathode-ray polarography in a NH₄OH/NH₄Cl supporting electrolyte after separation from titanium(IV) by extraction as dithizonate at pH 8.3 from citrate solution. The accuracy of the two methods was tested on synthetic samples by adding known quantities of zinc to a titanium solution freed from this element. Various titanium dioxide products commercially available were analysed, with satisfactory sensitivity (reproducibility 0.2% resp. 5%).

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Bestimmung von Zink in Titandioxid durch potentiometrische Titration und durch Kathodenstrahlpolarographie

Zusammenfassung Für Zinkgehalte > 0,1% wird die potentiometrische Titration mit Hexacyanoferrat(II) empfohlen, für niedrigere Gehalte (0,1 ppm) die Kathodenstrahlpolarographie in NH₄OH/NH₄C1-Grundlösung nach Abtrennung von Ti(IV) durch Dithizonatextraktion bei pH 8,3 aus Citratlösung. Zur Überprüfung der Genauigkeit der Methoden wurden synthetische Titanlösungen mit bekannten Zinkzusätzen analysiert. Befriedigende Ergebnisse wurden bei der Analyse verschiedener handelsüblicher Titandioxidproben erzielt (Reproduzierbarkeit: 0,2% bzw. 5%).

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Aspirant N.F.W.O.This work is part of the research sponsored by the Nationaal Fonds voor Wetenschappelijk Onderzoek.     

Analysis of germanium and germanium dioxide samples by mass-spectrometry and atomic emission spectroscopy

Three multielement methods: (1) inductively coupled plasma mass spectrometry (ICP-MS), (2) inductively coupled plasma atomic emission spectroscopy (ICP-AES), and (3) spark source mass spectrometry (SSMS) were used for the determination of additives in the samples of germanium and germanium oxide. The detection limits of direct SSMS and ICP-AES/ICP-MS were compared using the autoclave predissolution of germanium and germanium dioxide samples. It was shown that in the latter case, the detection limits could be significantly improved by the separation of germanium from analytes by distillation. In this case, the detection limits of such limiting elements like Th and U can reach the level n 10^?10 wt %.     

Spectrophotometric extractive determination of thiolactams with picric acid and silver

Summary Spectrophotometric Extractive Determination of Thiolactams with Picric Acid and Silver The thiolactams (Tpl, Tpr, Tkl, Tel) form with Ag⁺ and picric acid in solutions a complex with a molar ratio of AgTLpicric acid=1:1:1, which can be extracted into chloroform. The composition of the solid complexes of thiolactam is 121 (AgTLR). The formation of ternary complexes was used in the spectrophotometric determination of thiolactams in a concentration range of 0.2–5.0g/ml. Lactams do not influence the analytical response. The method is applicable to the determination of the thiolactams in a mixture of caprolactam and in xylene solutions during their synthesis.Communication presented at the European Conference on Analytical Chemistry (Euroanalysis V) Cracow, Poland, August 26–31, 1984.     

Spectrophotometric determination of chloride in plants

This indirect spectrophotometric determination of chloride in plants is based on displacement of thiocyanate from mercury(II) thiocyanate. Thiocyanate is extracted into nitrobenzene as tris(l,10-phenanthroline)iron(II) thiocyanate for measurement at 516 nm. Accuracy and precision are similar to those of the Volhard method but only about 2–200 mg samples are needed.     

Leaching of zinc and germanium from zinc oxide dust in sulfuric acid-ozone media

A new process of leaching zinc oxide dust by ozone oxidation in a sulfuric acid system was studied. The main factors affecting the leaching rate, such as ozone time, leaching temperature, initial acidity, leaching time, and liquid/solid mass ratio, were comprehensively investigated. The results show that leaching efficiency depends on all the above factors. The optimum conditions for leaching Zn and Ge from zinc oxide dust are as follows: ozone time 10 min, leaching temperature 90 ℃, initial acidity 160 g/L, leaching time 60 min, and liquid/solid mass ratio 7:1. Under the optimum conditions, the leaching rates of Zn and Ge are 95.79% and 93.65%, respectively. The leaching rates of zinc and germanium in the ozone leaching are 4.05% and 10.49% higher than those of the atmospheric leaching, respectively. Therefore, it is determined that ozone in solution plays a key role in rapidly oxidizing sulfide and releasing encapsulated germanium. Sulfuric acid-ozone media can efficiently extract Zn and Ge from zinc oxide dust.     

Spectrophotometric determination of germanium with Catechol Violet and cetyltrimethylammonium bromide

A ternary complex between germanium, Catechol Violet (CV) and cetyltrimethylanunoniuni bromide is proposed for the determination of germanium. The stoichiometric ratio Ge:CV is 1:2. Beer's law is obeyed from 0.1 to 1.0 ppm of Ge. The method is highly selective. Interference from Sn(IV), Fe(III), Bi(III), Cr(VI), Mo(VI), V(V) and Sb(III) in mg amounts is eliminated by extracting the germanium into carbon tetrachloride from 9M HC1 and then stripping into water before the photometric determination.     

Spectrophotometric extractive titrations for the determination of traces of metals

A modification of extractive titrations, spectrophotometric end-point determination, is proposed. There is no need to discard the organic layer after each extraction because specially constructed titration cells are used. Precise, rapid and selective determination of microgram amounts of single cations, and in favourable cases pairs of cations, is possible.     

Spectrophotometric determination of nitrogen dioxide in air

Summary A sensitive spectrophotometric method for the determination of trace amounts of nitrogen dioxide, after fixing it as nitrite in alkaline sodium arsenite solution, is described. The reaction is based on the diazo-coupling of p-nitroaniline with chromotrophic acid in acetate medium (pH 6±0.5). The azo dye formed has its absorption maximum at 515 nm, with a molar absorptivity of 3.7×10⁴ l mol^–1 cm^–1. Beer's law is obeyed over the range 0–20 g of nitrite. The relative standard deviation is 2.5% for ten determinations of 10 g of nitrite. The effect of interfering gases and ions on the determination is discussed. The method has been applied to the determination of residual nitrogen dioxide in a laboratory fume cupboard and the results are compared with those obtained by the widely used sulphanilamide — NEDA method. Down to 0.5 g of nitrite can be determined.     

Spectrophotometric extractive titrations-III Simultaneous determination of silver and copper in high purity lead

A procedure for the simultaneous determination of silver and copper in high-purity lead is given. After dissolution of the sample the majority of the lead is removed by precipitation with ammonium sulphate. Silver and copper are then determined by spectrophotometric extractive titration at pH 4.3-5.5 with dithizone. Changes of absorbance are measured at 550 mmu. The procedure has been checked by the method of standard additions and by comparison with conventional methods. The procedure is highly selective. The limit of determination is 2.5 x 10(-5)% of silver and 1.1 x 10(-5)% of copper.     

Determination of germanium in organo-germanium compounds

Summary A method is described for the determination of germanium in organic compounds after combustion in the oxygen flask. The yellow acetone-stabilised -form of germanomolybdate is formed and measured spectrophotometrically at 430 nm. Interference by silica is prevented by coating the oxygen flask with a non-stick coating material. The results obtained were within the usual limits for microanalysis (±0.3%).

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Zusammenfassung Ein Verfahren zur Germaniumbestimmung in organischen Verbindungen nach deren Verbrennung im Sauerstoffkolben wurde beschrieben. Das gelbe, mit Aceton stabilisierte -Germanomolybdat wird bei 430 nm spektrophotometrisch gemessen. Störungen durch Kieselsäure werden durch Auskleiden des Sauerstoffkolbens mit einem nichtklebenden Film vermieden. Die Resultate liegen innerhalb der mikroanalytischen Fehlergrenzen (±0,3%).

     

微波消解ICP-MS测试锌精矿中的铟和锗

本文提出了锌精矿通过微波消解,上ICP-MS测试得到铟和锗含量的方法。通过对样品分解方式的选择和质谱干扰扣除以及加标回收实验,得到铟的回收率在96.26%-98.70%,锗的回收率在99.6%-101%。通过检出限实验得到铟的检出限为0.001ug/g,锗的检出限为0.02ug/g。验证了本方法的可靠性。     

Spectrophotometric flow injection determination of chloride in ethanol

A flow injection procedure is described for the spectrophotometric determination of chloride in ethanol, based on the mercury(II) thiocyanate—iron(III) reaction. Effects of reagent composition and ethanol content of the sample are investigated in detail. The proposed system can analyse 120 samples of ethanol (94–100% v/v) per hour, with a relative standard deviation lower than 1%, when the chloride content ranges from 0.1–6.0 ppm. Recoveries of ca. 96% are found.     

Spectrophotometric determination of germanium in rocks after selective adsorption on sephadex gel

Germanium(IV) is preconcentrated on Sephadex G-25 from a carbonate solution (pH 12), and desorbed into 0.1 mol dm^?3 nitric acid. Iron(III) and tin(IV) in eluate were removed by a small cation-exchange column. The combination of the two columns made it possible to determine germanium in rocks at mg kg^?1 levels by spectrophotometry with phenylfluorone.     

Highly soluble germanium dioxide as a new source of germanium for derivatization with organic compounds

In modern germanium chemistry, toxic, corrosive and water- sensitive halogen and alkoxy derivatives, or poorly reactive polymeric dioxide are generally utilized. Recently developed highly water-soluble germanium dioxide was herein treated with diols and N-donor bases to produce novel highly reactive hydrophilic germanium source suitable for further derivatization.     

Spectrophotometric extractive titrations--V. Theoretical approach to titration of a single cation

The general equation of the titration curve for spectro-photometric extractive titrations is derived. The graphical location of the end-point is assumed and the significance of the general equation is discussed. Simple formulas for threshold pH and for sensitivity are obtained. An increased selectivity of spectrophotometric extractive titrations in comparison with that of the usual spectrophotometric extractive methods is demonstrated.