Determination Of Tellurium Research Articles

ChemInform Abstract: DIFFERENTIAL PULSE POLAROGRAPHIC DETERMINATION OF TELLURIUM BY USE OF MAXIMUM WAVE

AbstractDer differentialpulspolarographische Peak des Te(IV) in 1 mol/dm3 H3PO4‐Lösung liegt im Potentialbereich ‐0.7 bis ‐1.0 V (SCE).

Differential determination of tellurium(IV) and tellurium(VI) with sodium diethyldithiocarbamate, ammonium pyrrolidinedithiocarbamate and dithizone by atomic-absorption spectrophotometry with a carbon-tube atomizer

The extraction behaviour of tellurium(IV) and tellurium(VI) with sodium diethyldithiocarbamate, ammonium pyrrolidinedithiocarbamate and dithizone in organic solvents has been investigated by means of flameless atomic-absorption spectrophotometry with a carbon-tube atomizer. The selective extraction of tellurium(IV) and differential determination of tellurium(IV) and tellurium(VI) have been developed. With sodium diethyldithiocarbamate and carbon tetrachloride, when the aqueous phase/organic solvent volume-ratio is 5 and the injection volume in the carbon tube is 20 μl, the sensitivity for tellurium is 0.3 ng/ml for 1% absorption. The relative standard deviations are ca. 2%. The proposed methods have been applied satisfactorily to determination of tellurium(IV) and tellurium(VI) in various types of water.

Differential pulse polarographic determination of tellurium, application of catalytic hydrogen current

Tellurium deposited on the DME displaces the reduction potential of hydrogen and this results in the formation of a catalytic hydrogen current. Differential pulse polarographic measurement of the corresponding peak enables the determination of traces of tellurium down to the 1 ppb level. Using the method of standard addition, tellurium can be determined in the presence of all the metals usually accompanying tellurium in natural and industrial materials. In the cases when the material analyzed contains a larger excess of cadmium, silver or selenium, the separation of tellurium by extraction with methylisobutylketone should be employed.

Differential Pulse Polarographic Determination of Tellurium by Use of Maximum Wave

Abstract A differential pulse polarographic method for the rapid and simple determination of tellurium by use of maximum wave has been studied. Differential pulse polarographic (DP) peak of tellurium(IV) in 1 mol dm−3 phosphoric acid is observed in the potential range −0.7–−1.0 V vs. SCE. The peak current is very large in comparison with that in d.c. mode, or in normal pulse mode, being proportional to the concentration of tellurium(IV) between 10−8 and 10−7 mol dm−3 contents. The relative standard deviation for 3.94×10−8 mol dm−3 tellurium(IV) under representative sets of good conditions was 0.0342. The method has been applied to the determination of tellurium in carbon steel.

Differential pulse polarographic determination of tellurium. Application of catalytic hydrogen current

Tellurium deposited on the DME displaces the reduction potential of hydrogen and this results in the formation of a catalytic hydrogen current. Differential pulse polarographic measurement of the corresponding peak enables the determination of traces of tellurium down to the 1 ppb level. Using the method of standard addition, tellurium can be determined in the presence of all the metals usually accompanying tellurium in natural and industrial materials. In the cases when the material analyzed contains a larger excess of cadmium, silver or selenium, the separation of tellurium by extraction with methylisobutylketone should be employed.

Spectrophotometric determination of tellurium in trace quantities by use of an ion-association complex

The formation of an ion-association complex by the interaction of iodotellurate(IV) with cetyltrimethylammonium bromide is used as the basis of an extractive procedure to determine tellurium in the range 2.5–12.5 μg in a final aqueous phase volume of 20 ml. The method is simple, reliable and sensitive. Selectivity is achieved by separation of tellurium on aluminium hydroxide as collector.

Determination of tellurium in geochemical materials by flameless atomic-absorption spectroscopy

A method is described for the determination of tellurium at nanogram levels in rocks and in other complex materials by the use of flameless atomic-absorption spectroscopy. A very selective organic extraction procedure is applied to avoid matrix interference effects during extraction of Te and the atomization stage in the graphite furnace. Prior separation of iron and other interfering elements is achieved by a combined cupferron—ethyl acetate extraction. Tellerium is extracted from 6 M hydrochloric acid with MIBK and stripped into aqueous medium. Pipetting of the aqueous extract into the graphite furnace gives fairly good instrumental reproducibility (2–3% error). Detection limits of about 10 ppM Te for a 0.5-g sample have been achieved with the medium-performance apparatus used. Results for Te in some geochemical reference materials are reported. Indications are given for the determination of Sb and Mo in the same solutions.

Flame and flameless atomic-absorption determination of tellurium in geological materials

The sample is digested with a solution of hydrobromic acid and bromine and the excess of bromine is expelled. After dilution of the solution to approximately 3 M in hydrobromic acid, ascorbic acid is added to reduce iron(III) before extraction of tellurium into methyl isobutyl ketone (MIBK). An oxidizing air-acetylene flame is used to determine tellurium in the 0.1–20 ppm range. For samples containing 4–200 ppb of tellurium, a carbon-rod atomizer is used after the MIBK extract has been washed with 0.5 M hydrobromic acid to remove the residual iron. The flame procedure is useful for rapid preliminary monitoring, and the flameless procedure can determine tellurium at very low concentrations.

The determination of tellurium in weathered outcrop, mineralized and barren rock

Sensitive and specific methods have been developed for the determination of tellurium in a wide variety of rocks and minerals. X-ray fluorescence is used for concentrations above 1 μg g -1 and carbon furnace atomization a.a.s. for concentrations of 0.01–1μg g -1. The tellurium is separated by precipitation as elemental tellurium after dissolution in acid; alternative dissolution procedures have been investigated.

Spectrophotometric determination of tellurium in concentrates and brasses by chloroform extraction of the tellurium (IV) hexabromide-diantipyrylmethane complex after separations by iron collection and xanthate extraction

A method for determining 0.0001-0.10% of tellurium in copper, nickel, molybdenum, lead and zinc concentrates is described. After sample decomposition, tellurium is separated from most of the matrix elements by co-precipitation with hydrous ferric oxide from an ammoniacal medium. After reprecipitation of tellurium and iron, the precipitate is dissolved in 12M hydrochloric acid, tellurium(VI) is reduced to the quadrivalent state by heating, and separated from iron, lead and other co-precipitated elements by chloroform extraction of its xanthate. The yellow ion-association complex formed between tellurium(IV) hexabromide and diantipyrylmethane is extracted into chloroform from a 2M sulphuric acid-0.6M potassium bromide medium. The molar absorptivity of the complex is 1.82 x 10(3) l.mole(-1).mm(-1) at 336 nm, the wavelength of maximum absorption. Small amounts of iron, copper and molybdenum are co-extracted as xanthates under the proposed conditions but do not cause error in the result. Interference from antimony, which is co-extracted as the chloro-complex, is eliminated by washing the extract with water. The proposed method is also applicable to brasses.

The Determination of Trace Amounts of Tellurium and Selenium in Gallium Metal

Analytical methods have been developed for the separation, concentration and determination of trace quantities of tellurium and selenium from primary and scrap gallium metal. A chloroform extraction is made of the tellurium diethyldithiocarbamate complex at a pH of 8.5, followed by determination of tellurium by emission or atomic absorption spectroscopy. A toluene extraction is made of the 3,3'-diaminobenzidine complex of selenium which is measured spectrophotometrically at 420 nm. The limit of sensitivity for Te and Se is 0.5 ppM.

The determination of tellurium in leaded free-cutting steels by atomic-absorption spectrometry

A procedure is presented for the determination of tellurium within the range 0·005–0·08 per cent., with solvent conditions that permit its incorporation in a composite scheme that includes lead. In the preferred fuel-rich flame the background absorbance of iron and inter-element interferences are at a minimum.Good recoveries of tellurium when added to solutions of leaded and stainless steels, together with satisfactory reproducibilities for samples and good agreements with results by the slower turbidimetric procedure, are shown.

A highly sensitive fluorescent reaction for tellurium(VI) application to the determination of tellurium in selenium

A highly sensitive fluorescent reaction for tellurium(VI) application to the determination of tellurium in selenium

Simultaneous determination of tellurium and uranium by neutron activation analysis

Simultaneous determination of tellurium and uranium by neutron activation analysis

Direct photometric titration of tellurium

A direct photometric titration method has been developed for the determination of tellurium. Tellurium(IV) is titrated with potassium dichromate in 2–6 M nitric acid (or 1–4 M perchloric acid) at 380–430 nm (blue-violet filter). Selenium(IV) does not interfere.

Spectrophotometric determination of tellurium(IV) in a mixed hydrochloric acid—Acetic acid medium

Spectrophotometric determination of tellurium(IV) in a mixed hydrochloric acid—Acetic acid medium

Spectrochemical method for determination of tellurium in geological materials

Spectrochemical method for determination of tellurium in geological materials

Tellurium analysis in organotellurium compounds by atomic absorption spectroscopy

The application of atomic absorption spectroscopy to the determination of tellurium in organotellurium compounds is described. The samples are decomposed using a mixture of concentrated nitric and perchloric acids and an aqueous solution of telluric acid is used as the standard.

Determination of tellurium(IV) and selenium (IV) by anodic stripping voltammetry using co-deposition with copper

本報では,テルル(IV)と銅(II)またはセレン(IV)と銅(II)の共電着を利用するテルルおよびセレンのストリッピングボルタンメトリーを取り上げ,共電着および電解の基礎的条件について検討した.テルルの分析に関しては,銅(II)について1×10-4Mテルル(IV)について1×10-5～2.3×10-4Mおよび硝酸について0.64Mの溶液(5 ml)を5mAの定電流で15分間電解した.陰極には回転白金電極(作用電極,回転速度:800rpm),陽極に白金板(10mm×10mm)を用いた. 共電着後, 1M硫酸中で対極にSCEを用い,作用電極電位を0Vから0.21 V/minの速度で +1.0Vまで連続的に変化させ,回転白金電極上の共電着物を溶出させた.そのとき得られた溶出電流-電位曲線上のテルルの溶出ピーク(ピーク電位:+0.75V)のピーク面積から1×10-5～2.3×10-4Mのテルルが定量できた.各分析値の変動係数は2.5%以下であった.セレンに関しては,銅(II)について3×10-4M,セレン(IV)について1×10-5～2.2×10-4Mおよび硫酸について1Mの溶液(5ml)を電着電流20mAで20分間電解した.共電着後1M硫酸を支持電解質として,0Vから+1.5Vまで作用電極電位を連続的に変化させ,溶出曲線を記録した.他の分析条件はテルル分析のときと同じ条件であった.溶出曲線上のセレンのピーク面積(ピーク電位:+1.2V)から1.1×10-5～2.2×10-4Mのセレンが定量できた.各分析値の変動係数は2.1%以下であった.セレン,テルルの両方に関し,電解液温度は25℃に保った.

Determination of mercury, indium and tellurium in mercury indium telluride

Methods are given for the determination of mercury, indium and tellurium in a sample of mercury indium telluride. No prior separations are necessary and interferences that occur can readily be masked or compensated for. The sample is dissolved in a nitric acid-hydrochloric acid mixture. Indium and tellurium are examined polarographically in an electrolyte consisting of 2 M ammonium acetate-2 M acetic acid solution; for the determination of indium, the standard solution must contain an equivalent amount of tellurium. For the determination of tellurium in electrolytes consisting of 2 M ammonium acetate-2 M acetic acid or 0·5 M sodium carbonate solution, the indium can readily be masked by EDTA. Mercury is determined spectrophotometrically at 500 nm as the extracted dithizone complex. During dissolution of the sample, evaporation to dryness must be avoided as considerable amounts of mercury and tellurium may be lost. Accuracies in the region of ±1 per cent. are obtained on sample masses of 2 mg, although smaller samples can be examined without loss of accuracy.