Dosage colorimetrique du zinc dans le gallium de haute purete

A method for the determination of traces of zinc in high-purity gallium is proposed. The sample is dissolved in hydrochloric acid, the reaction being catalysed by platinum, and gallium is extracted as its chloro complex with ether; losses of zinc during this operation are determined radiochemically with ⁶⁵Zn as tracer. Zinc is then separated from other impurities in gallium by two extractions with dithizone, and determined colorimetrically as the dithizonate after excess of reagent has been removed. The limit of sensitivity of the method is 0.04 p.p.m.     

Spectrographic analysis of high-purity nickel oxide for twenty-one trace impurities, with use of a new buffer

A spectrographic method for the determination of twenty-one trace impurities in high-purity nickel oxide by the d.c. arc technique has been developed. A mixture of graphite and indium oxide in the ratio 2:1 is used as buffer. The lowest determination limits for various elements lie between 1 and 10 ppm with an average relative standard deviation of +/- 12%.     

Application of platinum gauze activated by hydrogen to the adsorption separation of silver traces and their determination by aas or spectrophotometry

A method ("electrosorption") has been developed for separation of silver from copper by its deposition through internal electrolysis with hydrogen adsorbed on a platinum surface. The silver can then be stripped and determined by atomic-absorption spectrometry or the dithizone method. The activation of the platinum surface with adsorbed hydrogen can be achieved either electrolytically or by passing hydrogen gas through the solution in which the platinum is immersed. The method of electrosorption has been successfully applied to determination of trace levels of silver in copper metal.     

Determination of platinum and palladium in environmental samples by graphite furnace atomic absorption spectrometry after separation on dithizone sorbent

A graphite furnace atomic absorption method of platinum and palladium determination after their separation from environmental samples has been presented. The samples were digested by aqua regia and the analyte elements were separated on the dithizone sorbent. The procedure of sorbent preparation was described and their properties were established. Two various procedures of elution by thiourea and concentrated nitric acid were described and discussed. The low limit of detection was established as 1 ng g⁻¹ for platinum and 0.2 ng g⁻¹ for palladium.There was also investigated the behaviour of platinum and palladium introduced into the soil in various chemical forms.     

Extractive separation and spectrophotometric determination of palladium and platinum with dithizone in the presence of stannous chloride

The conditions [acid used, presence of chloride and tin(II)] for the extractive separation and spectrophotometric determination of palladium and platinum as the dithizonates Pd(HDz)(2) and Pt(HDz)(2) have been examined. In the absence of stannous chloride platinum does not undergo extraction. Conditions for the separation and determination of these metals in the presence of mercury, gold and copper, which are also extracted with dithizone into carbon tetrachloride or chloroform under the conditions suitable for palladium (1M sulphuric acid/0.1M hydrochloric acid), have been defined. The mercury and gold dithizonates are formed quickly and can be removed before the palladium and platinum compounds have had time to form. They can be decomposed with iodide. Copper dithizonate is decomposed by reduction with tin(II). The proposed procedure has been applied to the determination of palladium in technical platinum metal.     

Matrix elimination ion chromatography method for the determination of trace levels of anionic impurities in high purity cesium iodide

In the present study an ion chromatographic method based on matrix elimination has been developed for the determination of anionic impurities in high purity cesium iodide crystals. The presence of impurities has a detrimental effect on the characteristics of detectors based on cesium iodide crystals. In particular, oxygen-containing anions inhibit the resolving power of scintillators and decrease the optical absorption. The quantitative determination of anions (fluoride, chloride, bromide, nitrate, phosphate, and sulphate) simultaneously in the high-purity cesium iodide crystals has not been carried out before. The large concentration of iodide poses a challenge in the determination of anions (especially phosphate and sulphate); hence, matrix elimination is accomplished by adopting a sample pretreatment technique. The method is validated for linearity, accuracy, and precision. The limit of detection for different anions is in the range of 0.3-3 μg/g, and the relative standard deviation is in the range of 4-6% for the overall method.     

Spectrophotometric determination of platinum in glass after extraction with polyurethane foam

A spectrophotometric method has been developed for determination of trace amounts of platinum in glass. The method is based on the extraction of platinum(II) from 1M hydrochloric acid containing 0.2M stannous chloride and 4 x 10(-4)M dithizone onto polyurethane foam, elution with acetone (containing 3% v/v concentrated hydrochloric acid) and measurement of the absorbance of the eluate at 530 nm. Beer's law is obeyed up to 10.0 microg/ml Pt. The minimum platinum level in the eluate that can be determined by this method is 0.1 microg/ml.     

Trace analysis of high-purity graphite by LA-ICP-MS

Laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been established as a very efficient and sensitive technique for the direct analysis of solids. In this work the capability of LA-ICP-MS was investigated for determination of trace elements in high-purity graphite. Synthetic laboratory standards with a graphite matrix were prepared for the purpose of quantifying the analytical results. Doped trace elements, concentration 0.5 microg g(-1), in a laboratory standard were determined with an accuracy of 1% to +/- 7% and a relative standard deviation (RSD) of 2-13%. Solution-based calibration was also used for quantitative analysis of high-purity graphite. It was found that such calibration led to analytical results for trace-element determination in graphite with accuracy similar to that obtained by use of synthetic laboratory standards for quantification of analytical results. Results from quantitative determination of trace impurities in a real reactor-graphite sample, using both quantification approaches, were in good agreement. Detection limits for all elements of interest were determined in the low ng g(-1) concentration range. Improvement of detection limits by a factor of 10 was achieved for analyses of high-purity graphite with LA-ICP-MS under wet plasma conditions, because the lower background signal and increased element sensitivity.     

Preparation of high-purity Fluorozirconate Glasses

The properties of glasses of quaternary and quinary systems synthesized on the basis of zirconium fluoride are shown. In particular, the influence of impurities, phase inhomogeneities, and gaseous bubbles on their optical properties are discussed. Methods for the preparation and characterization of high-purity fluorozirconate glasses as quinary systems are reported.     

Substoichiometric determination of traces of palladium by radioactive isotope-dilution analysis

A radioactive isotope-dilution method for the determination of traces of palladium has been developed. It is based on the solvent extraction of palladium dithizonate from acid solution by means of a substoichiometric amount of dithizone in carbon tetrachloride. The separation has been applied to the determination of traces of palladium in platinum, the rocks W-1 and PCC-1 and a biological material (kale). Amounts of palladium down to 3 ng have been 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.     

Sample Preparation for Emission Spectrographic Determination of Impurities in Elemental Boron

Abstract

Accurate spectrographic determination of impurities in high-purity elemental boron requires that impurity elements be concentrated and collected in a suitable matrix while boron is separated from the sample. A method of acid dissolution followed by boron volatilization through an acetic anhydride and methanol treatment has been developed. This procedure is considerably faster and leaves lower residual boron concentrations than other methods. The mild conditions used to volatilize boron avoid the loss of any impurity elements from the sample.     

Determination of trace elements and radioactive materials by substoichiometric isotope dilution analysis

Substoichiometric isotope dilution analysis has been applied for the determination of trace elements in liquid samples, of carrier content in radioisotope solution and of concentration of organic reagent. Cu in mineral acids and in ZnSe single crystal was determined by the substoichiometric extraction with dithizone. The values of 1.8 and 0.018 ppm in nitric acid and distilled one and of 1.4 and 0.44 ppm in ZnSe were obtained. Cu and P carrier contents in⁶⁴Cu and³²P solutions were determined by the substoichiometric extractions with dithizone in CCl₄ and with molybdic acid into MIBK in the series of the solutions adding various amounts of Cu or P carrier. An analogous method has been applied for the determination of dithizone and diethyldithiocarbamate solutions. The method was also applied for the determination of⁶⁰Co radioactivity in environmental samples. The analytical result of water samples is described.     

Determination of trace impurities in high-purity cadmium by high-resolution inductively coupled plasma mass spectrometry.

Trace impurities in high-purity cadmium were determined by high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). To overcome some potentially problematic spectral interference, measurements were acquired in both medium and high-resolution modes. The matrix effects due to the presence of excess HCl and cadmium were evaluated. The optimum conditions for the determination were tested in this experiment and discussed. The detection limits ranged from 0.01 to 0.27 microg g-1, depending on the elements. The results for the determination of 22 trace elements in high-purity cadmium are presented.     

Substoichiometric determination of chromium by neutron activation analysis

A method of radioactivation analysis has been developed for the determination of chromium. It is based on the substoichiometric extraction of chromium diethyldithio-carbamate into methyl-isobutyl-ketone from acetate buffer solution in the presence of EDTA and potassium cyanide. The method has been applied for the determination of chromium in high-purity calcium carbonate and NBS glasses as standard reference materials.     

Potentials of thermal lens spectroscopy for polymethacrylate optical sensors

The sensitivity of the earlier proposed procedures for the determination of iron(II, III) with 1,10-phenanthroline, silver(I) with dithizone, mercury with copper(II) dithizonate, copper(II) with lead diethyldithiocarbamate, and ascorbic acid with 2,6-dichlorophenolindophenol using polymethacrylate optical sensitive elements for solid phase spectrophotometry is enhanced through the use of thermal lens spectrometry as the most sensitive method of molecular absorption spectroscopy. The limits of detection for all photometric reactions in the polymethacrylate matrix are reduced by an order of magnitude (to 10 nM) without substantial changes in the experimental conditions.     

The use of neutron activation for routine analysis of pure iron and chromium

A method is presented for the routine analysis of high-purity iron and chromium by neutron activation analysis. The impurities determined are those which are significant in the control of the purification processes. Nine elements are determined in iron without separation; Co, Cr and Mo can also be determined after an anion-exchange separation. In chromium, a single elution on an anion exchanger allows the detection of nine significant impurities. For the determination of nickel a special method is used. All these methods were chosen to obtain the most comprehensive analytical procedure at the lowest cost.     

共沉淀分离富集-电感耦合等离子体原子发射光谱法测定高纯氧化钨中痕量金属杂质

提出了以Ｌａ（ＯＨ）３为共沉淀剂，对高纯氧化钨中的痕量金属杂质元素经共沉淀预分离富集后进行ＩＣＰ－ＡＥＳ测定的分析方法。探讨了影响杂质元素回收率和钨残留量的若干因素，确定了合适的分离富集条件。合成试样和标准样品的测试结果表明： Ｂｉ、Ｃａ、Ｃｄ、Ｃｏ、Ｃｕ、Ｆｅ、Ｍｇ、Ｍｎ、Ｎｉ、Ｐｂ、Ｓｂ、Ｓｎ、Ｔｉ等元素能被定量分离回收，回收率和精密度均令人满意。     

Determination of impurities in high-purity niobium(V) oxide by high-resolution continuum source graphite furnace atomic absorption spectrometry after sorption preconcentration

Method of sorption–atomic-absorption determination of Co, Cr, Cu, Fe, Mn, and Ni in samples of high-purity Nb₂O₅ with heterochain S,N-containing sorbents was developed. The method is based on the sorption preconcentration of trace impurities followed by their determination by high-resolution continuum source graphite furnace atomic absorption spectrometry (HR CS GFAAS). Selectivity of three original inhouse synthesized S,N-containing heterochain sorbents was studied. The recoveries of Co, Cr, Cu, Fe, Mn, and Ni using heterochain sorbents OKS, MTH, and GLSH were 100, 80, and 76%, correspondingly. Sorbent “OKS”, which provided the quantitative recovery of trace impurities, was chosen for further research. The sorption conditions for chloride solutions of different acidities (0.1–3 M HCl) were studied and optimized. Using the conditions established for the sorption and HR CS GFAAS analysis, trace Co, Cr, Cu, Fe, Mn, and Ni were determined in high purity Nb₂O₅ with a relative error less than 5%. The trueness control of the obtained results is confirmed by the “added–found” method. The developed method allows us to determine concentrations of analytes: 0.02–0.20 ppm Co, 2.0–3.3 ppm Cr, 0.2–1.5 ppm Cu, 6.0–21.0 ppm Fe, 0.6–0.8 ppm Mn, and 2.8–3.5 ppm Ni. The proposed methodology can be successfully extended to the determination of various trace elements in other high-purity inorganic materials.     

高纯钛的辉光放电质谱法多元素分析

采用辉光放电质谱法(GD-MS)测定高纯钛中Mg、Al、Cr、Fe、V、Mn、Co、Ni、Cu、Zn、As、Sn、Sb、Ta、W、Pb、Bi等痕量杂质元素,并对GD-MS工作参数及条件进行了优化。主要元素与内标校正ICP-MS法定量分析的结果一致,对结果差异的原因进行分析,论述了Element GD辉光放电质谱仪在痕量杂质元素分析方面的优势。