Polarographic studies of indium(III) complexes with some disubstituted pyridines

Complex formation of indium(III) with three disubstituted pyridines, viz., 2,3-dihydroxypyridine, 2-amino-3-hydroxypyridine and 3-hydroxypyridine-2-thiol has been studied polarographically (=0.1; temp.=25±0.1°C). All the systems show reversible electrode behaviour.DeFord andHume method as modified byIrving has been applied for determining composition and stability constants. Distribution of different species as a function of ligand concentration has been calculated and shown graphically.With 4 Figures     

Polarographic determination of indium(III) after salting-out extraction of the bromide complex into acetonitrile

A simple and sensitive method has been developed for the polarographic determination of indium(III) after solvent extraction into acetonitrile, salted-out from aqueous solution with sodium bromide. The extracted indium(III)-bromide complex gives a well-defined d.c. wave with E(1 2 ) = -0.69 V vs. SCE. The wave-height is directly proportional to the concentration of indium(III) from 1.6 x 10(-6) to 3.0 x 10(-4)M with respect to the original aqueous solution. In the a.c. polarographic method, a linear calibration curve is obtained for indium(III) over the concentration range from 1.6 x 10(-6) to 1.5 x 10(-5)M, and interference from most foreign ions can be eliminated. In particular, 10.0 mg of Fe(III) and 2.5 mg of Tl(III) are tolerated when 1.0 g of ascorbic acid is added. The lower limit of determination is 8 x 10(-8)M indium(III) by the square-wave polarographic method.     

Polarographic determination of iron(II) and iron(III) complexes with edta

The iron(II) and iron(III) complexes with EDTA can be determined separately and in mixtures in acetate-buffered medium at pH 4.0. The E_{$\text{1}\text{2}$}values are in the range ?0.105 to ?0.112 V vs. SCE. Linear calibration plots are obtained over the range 0–1.0 mM for each oxidation state. A sample-handling procedure for avoiding oxidation of iron(II) species is described. It is shown that the acetate buffer system does not affect the stability of the iron-EDTA complexes.     

Simultaneous determination of gallium(III) and indium(III) by derivative spectrophotometry

A simple, selective and sensitive derivative spectrophotometric method is proposed for the simultaneous determination of gallium(III) and indium(III) in mixtures using 1-(2-pyridylazo)-2-naphthol in cationic micellar medium, without any prior separation. Beer's law is obeyed between 2.80x10(-1)-3.63 and 4.60x10(-1)-9.20 mug ml(-1) concentration of Ga(III) and In(III) at 550 and 542 nm, the isodifferential points of indium and gallium complexes in the first-order derivative mode, respectively. The proposed method is successfully applied for the determination of gallium and indium in standard reference materials and synthetic binary mixtures with a relative error of +/-2.07 and +/-2.55%, respectively.     

Polarographic determination of Ce(III) and Tm(III) using rare earth-DBF-chlorophosphonazo complex

The electrochemical behaviour of the DBF—chlorophosphonazo (DBF—CPA)—rare earth (RE) complex has been investigated in this paper. A highly sensitive polarographic adsorption wave was found in the RE(III)—DBF—CPA system and a new method for determination of trace total RE(III) has been established. The limit of detection was 1.8 × 10⁻⁸M. The results of determination of the total RE(III) content in Chinese standard reference materials of cast-iron and alloy steel were in good agreement with the certified values. The polarographic adsorptive waves of Ce(III) and Tm(III)—DBF—CPA overlap seriously. In order to improve the selectivity of determination, a non-linear regression model was employed to fit the peak height of the polarographic wave and the concentrations of Ce(III) and Tm(III). The predictive accuracy of this model for simulant mixtures was satisfied.     

Polarographic determination of osmium with the osmium(VIII)-cerium(IV)-arsenic(III) system

A highly sensitive and novel polarographic method has been developed for determination of ultratrace amounts of osmium, based on the catalysis of the cerium(IV)-arsenic(III) reaction by osmium(VIII). The reaction rate is monitored by measuring the arsenic(III) with a single-sweep oscillopolarograph. Osmium concentrations from 7.0 x 10(-11) to 5.0 x 10(-9)M can be determined by the initial rate method. The method has been applied to determination of osmium in refined ore and chlorination residues with satisfactory results.     

Polarographic determination of indium in lead and zinc metals

A rapid polarographic method for determining low milligram quantities of indium in lead metal containing 2% of zinc and in zinc metal containing 2% of lead is described. In a supporting electrolyte of 10% D-tartaric acid adjusted to pH 2.0, a well-defined wave for indium is obtained after the precipitation of lead as the sulfate.     

Spectrophotometric determination of indium(III) with the polymeric chromogenic reagent PV · FPAQ

Summary The polymeric chromogenic reagent PV · FPAQ has been synthesized by condensing 7-(4-formylphenylazo)-8-quinolinol (FPAQ) with poly(vinyl alcohol) (PVA). With indium(III) the reagent forms in weakly acidic media a water-soluble yellow complex, whose absorption maximum is at 445 nm. The molar absorptivity of the complex was found to be 3.16×10⁴ l · mol^–1 · cm^–1 and Sandell's sensitivity 3.6 ng · cm^–2. Beer's law is obeyed over the range 0–30 g of indium(III) per 25 ml of solution. A Spectrophotometric method for the determination of indium has been worked out and applied to synthetic and authentic samples with satisfactory results.

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Spektrophotometrische Bestimmung von Indium(III) mit dem polymeren chromogenen Reagens PV · FPAQ

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Lecture given at the 2nd National Symposium for Inorganic Micro and Trace Analysis, Xi-An, Peoples Republic of China, September 1988 (see [3])     

Polarographic determination of In(III) and Cd(II) in the presence of a crown ether

Summary The simultaneous determination of In(III) and Cd(II), whose reduction potentials are very close to each other, was investigated by polarography in the presence of a crown ether such as 12-Crown-4, 15-Crown-5, or 18-Crown-6. An addition of the crown ether shifts the reduction potential of In(III) towards the negative side, its current remaining unchanged, while that of Cd(II) almost did not change, also leaving the wave current constant. Therefore, the difference in reduction potentials between two ions became appreciably large for the simultaneous determination by polarography.     

Heterobimetallic heterocyclic derivatives of indium(III)

Reactions of InCl₃ with potassium salts of bifunctional tridentate (L¹H₂HOC₆H₄CH NCH₂CHMeOH) and monofunctional bidentate (L²HHOC₆H₄CHN-i-Bu) Schiff bases in 1:1 and 1:2 molar ratio in benzene afford complexes In(L¹)Cl and In(L²)₂Cl, respectively. On reaction with potassium isopropoxymetallates KB(O-i-Pr)₄, KAl(O-i-Pr)₄, KTi(O-i-Pr)₅, and KNb(O-i-Pr)₆, they produce interes- ting heterobimetallic heterocyclic complexes. These are characterized by elemental (N, B, Al, Ti, and Nb) analyses, molecular weight measurements, and spectral [IR, NMR (¹H, ¹³C, ¹¹B, and ²⁷Al)] studies. Probable structures are suggested for them. © 2003 Wiley Periodicals, Inc. 15:21–25, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/.hc10206     

The solvent extraction of indium(III) with carboxylic acids

The extractions of l0^-5–10^-7M indium, from aqueous 0.1 M sodium perchlorate solutions into various organic media containing different concentrations of monocarboxylic acids and into pure monocarboxylic acids have been studied. Both saturated and unsaturated acids have been employed; the number of carbons in the acids was l–18. Detailed studies of one of the better systems, hexanoic acid in chloroform, have been carried out, the system has been described with a general overall equation, and identifications of the major species have been proposed.     

The coextraction of rhenium with pyridylazonaphtholates of indium,iron(III) and thallium(III)

The extraction of indium, iron(III) and thallium(III) complexes with 1-(2-pyridylazo)-2-naphthol is enhanced by the presence of perrhenate ion. Rhenium is coextracted with these metals in the form of ion associates of the InA₂⁺ReO₄^- type. where A is the anion 1-(2-pyridylazo)-2-naphthol.