Determination of iron in cadmium and cadmium telluride

A procedure is described for the determination of iron in the 10(-6)-10(-4)% range in cadmium and cadmium telluride. Acetylacetone is used for the separation of iron from cadmium, and the iron is determined spectrophotometrically with bathophenanthroline.     

Determination of traces of lead,cadmium and zinc in copper by an arc-nebulization and flame atomic absorption technique

Arc-nebulization (a thermal nebulization technique) is used to form an aerosol of cadmium, lead and zinc. An open arc chamber of simple operation and an ejector of high efficiency are described which are adaptable for use with any flame atomic absorption spectrometer. Limits of detection better by one or two orders of magnitude than those achieved by conventional flame a.a.s. methods were obtained viz., 43 ng Pb, 5 ng Cd, 7 ng Zn (equivalent to 0.7, 0.08 and 0.11 ppm, respectively, in copper). Calibration with matrix-free solutions was possible for lead and cadmium but not for zinc. The spectral interference of copper on absorbance at the most sensitive zinc line (213.856nm) and the efficiency of arc nebulization of cadmium are also discussed.     

Determination of traces of lead, thallium, and cadmium in zinc salts by means of anodic stripping voltammetry

Summary A method is described by which it is possible to determine traces of lead, thallium, and cadmium in zinc salts by means of anodic stripping voltammetry in a concentration range of about 0.1 to 20 ppm, with a possible error of 10 to 20%. As far as could be investigated, no other elements interfere with the determination.

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Zusammenfassung Eine Methode wird beschrieben zur Bestimmung von Blei, Cadmium und Thallium in Zinksalzen durch anodische Amalgamvoltammetrie. Das Verfahren ist geeignet für Gehalte von etwa 0,1–20 ppm, bei einem möglichen Fehler von 10–20%. Soweit nachgeprüft werden konnte, wird die Bestimmung von keinen anderen Elementen gestört.

     

Determination of traces of boron and cadmium in manganese sulphate solutions

Summary A well established method to calibrate ²⁵²Cf neutron sources makes use of a manganese bath technique based on the measurement of the induced ⁵⁶Mn-,-radioactivity. The knowledge of the impurities present in the bath is required because they may affect the results of the source strength measurements by their neutron absorption properties. Some specific impurities which may introduce a significant correction must be quantified and selective methods have to be used for their determination. The determination of two of these specific impurities, having a high capture cross section for neutrons, the boron and the cadmium, is described; it is based on spectrophotometry with curcumin (for B) and on pulse polarography (for Cd). Analytical results obtained on baths prepared in different laboratories are given. Errors are ±4–7% for B and ±3% for Cd.

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Bestimmung von Bor- und Cadmiumspuren in Mangansulfatlösungen

Zusammenfassung Eine übliche Methode zur Eichung von ²⁵²Cf-Neutronenquellen basiert auf der Manganbad-Technik, wobei die induzierte ⁵⁶Mn-,-Aktivität gemessen wird. Die Ergebnisse können durch Verunreinigungen des Bades beeinflußt werden. Methoden zu deren selektiver Erfassung sind daher notwendig. Die Bestimmung von Bor und Cadmium, die einen besonders hohen Einfangquerschnitt für Neutronen haben, wird beschrieben. Sie beruht auf der spektralphotometrischen Bestimmung mit Curcumin (für B) bzw. auf der pulspolarographischen Bestimmung (für Cd). Analysenwerte für verschiedene MnSO₄-Bäder werden verglichen. Die Fehler liegen im Bereich von ±4–7% (für B) und ±3% (für Cd).

     

Determination of traces of iron and gallium in high-purity aluminium

Summary A procedure is described suitable for determining iron and gallium down to the levels present in 99.999% pure aluminium. Copper, cobalt, manganese, and lanthanum do not interfere. A single determination takes about two hours.The precision of the method is within 0.1g iron at the 2-g iron level and within 0.4g of gallium at the 2-g gallium level per gram of metal.

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Zusammenfassung Ein Verfahren zur Bestimmung von Bisen und Gallium in 99,999%igem Aluminium wird beschrieben. Kupfer, Kobalt, Mangan und Lanthan stören nicht. Eine Einzelbestimmung dauert ungefähr 2 Stunden. Die Genauigkeit des Verfahrens beträgt 0,1g Fe und 0,4g Ga bei Anwesenheit von 2g des betreffenden Elementes pro Gramm Metall.

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Résumé On décrit un procédé permettant le dosage du fer et du gallium jusqu'aux teneurs présentes dans l'aluminium pur à 99,999%. Le cuivre, le cobalt, le manganèse et le lanthane n'interfèrent pas. Un seul dosage demande environ 2 heures.La précision de la méthode est de 0,1g de fer pour 2g de fer présent et de 0,4g de gallium pour 2g de gallium présent par gramme de métal.

     

粗锌中镉的测定方法研究

样品用硝酸-盐酸分解,采用扣除背景的方式消除高含量的锌对低含量镉测定的影响。优化了镉测定的仪器条件,建立了粗锌中镉含量的测定方法。用于测定粗锌中镉,结果的相对标准偏差(RSD,n=11)为0.95%～6.3%。按照实验方法对粗锌样品进行加标回收实验,加标回收率为98.0%～102%。与ICP-AES法测定结果基本一致,能满足日常对粗锌中镉含量的测定要求。     

粗锌中镉的测定方法研究

采用火焰原子荧光法（FAFS）和电感耦合等离子体质谱法（ICP-MS）测定铅锌矿中的镉. 通过对比研究,两种方法的校准曲线相关系数良好（r>0.999 5）,方法检出限、准确度和精密度均符合质量规范要求. 经过铅锌矿实际样品的比对,两种方法不存在显著性差异. FAFS法比ICP-MS法测定时间短,精密度高,适用于大批量铅锌矿样品的测定.

     

Determination of traces of cadmium in alloy steels by anodic stripping voltammetry

Concentrations of cadmium of the order of 0.1 ppm in alloy steels containing large concentrations of chromium and nickel (ca. 17 and 13% respectively), about 0.1% of copper and a number of metals at low concentrations, were determined by anodic stripping voltammetry with a hanging mercury-drop electrode in 1M hydrochloric acid. Cadmium was separated on Dowex 50W-X8 cation-exchanger in a medium at pH 1.3 containing excess of EDTA. Mercury-film electrodes cannot be used for this determination, because the peak for cadmium is distorted by evolution of hydrogen on the electrode support. The relative standard deviation of the determination of 0.44 ppm of cadmium in steel is 3.2% and the confidence limits for 95% probability are 0.44 +/- 0.02 ppm. The error in the cadmium recovery does not exceed + 8%.     

Determination of traces of zinc by fluorimetrically indicated complexometric titrations

Zinc forms fluorescent complexes with 8-hydroxyquinoline-5-sulphonic acid (HQS) in the pH region 7-10. The stability of these complexes is such that two different titration procedures are possible: the titration of zinc with HQS and the titration of zinc with EDTA in the presence of HQS. For both procedures the choice of the titration conditions is described. Also two separation procedures for zinc are described, especially suitable in connection with the EDTA titration. The practical results show that zinc in concentrations larger than 10(-6)M (0.05 mug/ml) can be titrated with good precision.     

Characterization of neutron transmuted zinc traces in pure copper materials by isotope dilution mass spectrometry

The neutron transmutation doping (NTD) of highly pure copper with zinc was investigated as a promising means of achieving controlled gradation of the zinc content in the range 1-20 microg g(-1). The doping process leads to the enrichment of two stable isotopes 64Zn and 66Zn in a ratio which differs from that of natural isotopic distribution. Mass spectrometric investigations by thermal ionization mass spectrometry (TIMS) were performed to validate the results obtained by gamma spectrometry. The investigations included both determination of the isotopic ratios of the doped zinc isotopes and the analysis of the accumulated zinc contents by isotope dilution (ID) analysis. Thereby a sample-specific correction of the blank could be performed because the isotope 68Zn was not influenced, because of the transmutation process. The results obtained by TIMS prove the strict proportionality of the doped zinc content, in the range 5 to 20 microg g(-1), to the neutron fluence. Comparison with gamma spectrometric results showed a very good agreement within the uncertainties.     

Characterization of neutron transmuted zinc traces in pure copper materials by isotope dilution mass spectrometry

The neutron transmutation doping (NTD) of highly pure copper with zinc was investigated as a promising means of achieving controlled gradation of the zinc content in the range 1–20 μg g^–1. The doping process leads to the enrichment of two stable isotopes ⁶⁴Zn and ⁶⁶Zn in a ratio which differs from that of natural isotopic distribution. Mass spectrometric investigations by thermal ionization mass spectrometry (TIMS) were performed to validate the results obtained by gamma spectrometry. The investigations included both determination of the isotopic ratios of the doped zinc isotopes and the analysis of the accumulated zinc contents by isotope dilution (ID) analysis. Thereby a sample-specific correction of the blank could be performed because the isotope ⁶⁸Zn was not influenced, because of the transmutation process. The results obtained by TIMS prove the strict proportionality of the doped zinc content, in the range 5 to 20 μg g^–1, to the neutron fluence. Comparison with gamma spectrometric results showed a very good agreement within the uncertainties.     

Determination of traces of thallium in zinc and cadmium metals and process solutions by atomic-absorption spectrophotometry after extraction with di-isopropyl ether and reductive stripping

The bromo-complex of thallium(III) is extracted into di-isopropyl ether and reductively stripped into sodium sulphite solution, which is then analysed for thallium by atomic-absorption spectrophotometry. Thallium in zinc and cadmium metals and process solutions can be determined by this method.     

Quantitative separation of zinc traces from cadmium matrices by solid-phase extraction with polyurethane foam

A system for separation of zinc traces from large amounts of cadmium is proposed in this paper. It is based on the solid-phase extraction of the zinc in the form of thiocyanate complexes by the polyurethane foam. The following parameters were studied: effect of pH and of the thiocyanate concentration on the zinc extraction, shaking time required for quantitative extraction, amount of PU foam necessary for complete extraction, conditions for the separation of zinc from cadmium, influence of other cations and anions on the zinc sorption by PU foam, and required conditions for back extraction of zinc from the PU foam. The results show that zinc traces can be separated from large amounts of cadmium at pH 3.0±0.50, with the range of thiocyanate concentration from 0.15 to 0.20 mol l⁻¹, and the shaking time of 5 min. The back extraction of zinc can be done by shaking it with water for 10 min. Calcium, barium, strontium, magnesium, aluminum, nickel and iron(II) are efficiently separated. Iron(III), copper(II) and cobalt(II) are extracted simultaneously with zinc, but the iron reduction with ascorbic acid and the use of citrate to mask copper(II) and cobalt(II) increase the selectivity of the zinc extraction. The anions nitrate, chloride, sulfate, acetate, thiosulphate, tartarate, oxalate, fluoride, citrate, and carbonate do not affect the zinc extraction. Phosphate and EDTA must be absent. The method proposed was applied to determine zinc in cadmium salts using 4-(2-pyridylazo)-resorcinol (PAR) as a spectrophotometric reagent. The result achieved did not show significant difference in the accuracy and precision (95% confidence level) with those obtained by ICP–AES analysis.     

直读光谱法测定析出锌中铅、铜、铁、镉、锡、铝的含量

研究了湿法冶炼产出的析出锌,经过冲床冲压脱模、马弗炉高温熔化、模具浇铸成型、车床切削等过程,于直读光谱仪上测定析出锌中铅、铜、铁、镉、锡、铝含量的方法.通过实验确认了仪器的工作条件、熔样器皿、熔样温度、析出锌取样位置,并对熔样铸锭后铅、铜、铁、镉、锡、铝的偏析情况进行了分析,铅最大偏差达到30％,经玻璃棒搅动后保温,铅...     

Determination of traces of palladium using radioactive zinc dithizonate as a reagent

A radioreagent method for the analysis of traces of palladium using radioactive zinc dithizonate as the reagent has been developed. The method is rapid, highly selective and palladium concentration down to 2 g present in 10 ml solution can be measured.     

Determination of zinc and cadmium by flow injection analysis and chemiluminescence

Zinc (10–100 ng ml^-1 and cadmium (20–200 ng ml^-1) are successively eluted from an ion-exchange column and determined by their inhibition of the cobalt-catalyzed chemiluminescence generation from luminol.     

Determination of traces of mercury using radioactive zinc dithizonate as a reagent

A radioreagent method for the analysis of traces of mercury using radioactive zinc dithizonate as the reagent has been developed. As small as 0,2 μg of mercury can be determined using this technique. Possible interferences from most of the metals which displace zinc from zinc dithizonate can be removed by a simple separation procedure. The method was tested by analyzing the NBS reference standard SRM 1064 and our value was found to be in agreement with the value certified by NBS. This paper was presented at the South-East and South-West ACS Regional Meeting, Memphis, Tenn., October 29–31, 1975.     

Electrochemical stripping determination of traces of copper, lead, cadmium and zinc in zirconium metal and zirconium dioxide

Procedures have been developed for the determination of copper, lead, cadmium and zinc in zirconium metal and zirconium dioxide, at concentrations of 1 ppm or less. Zirconium metal was dissolved in suphuric acid, and zirconium dioxide decomposed under pressure with hydrofluoric acid. Sample solutions were prepared in dilute sulphuric acid. For the stripping determination, the sample solution was either mixed with a complexing tartrate base electrolyte or the pre-electrolysis was carried out in acid solution, with the acid solution being exchanged for a pure base electrolyte (e.g. an acetate buffer) for the stripping step. The stripping step was monitored by d.c., differential pulse and Kalousek commutator voltammetry and the three methods were compared. A stationary mercury-drop electrode can generally be used for all the methods, whereas a mercury-film electrode is suitable only for the d.c. voltammetric determination of copper, lead and cadmium, as pulse measurements with films are poorly reproducible and the electrodes are easily damaged. The relative standard deviation does not exceed 20%. Some samples contained relatively large amounts of copper, which is best separated by electrodeposition on a platinum electrode.