Oximidobenzotetronic acid as a reagent for the separation and gravimetric determination of palladium and cobalt

Oximidobenzotetronic acid is recommended for the separation and gravimetric determination of palladium and cobalt An ethanolic solution of the reagent quantitatively precipitates palladium(II) from solutions which are 0.75 N in acid up to pH 5.1, the complex is weighed as Pd(C₉H₅NO₄)₂. Cobalt(II) can be determined in the filtrate after the precipitation of palladium. With 0.5 N acid solutions, no interference was found from Pt(IV), Ir(IV), Rh(III), Ru(III), Os(IV), Au(III), Ag(I), Cu(II), Fe(III), Ni(II), Hg(II). Pb(II), Bi(III), Cd(II), As(V), Se(VI), Te(IV), Mo(VI), Sb(III), Al(III), Cr(III), Zn(II), Ti(IV), Zr(IV). acetate, oxalate, citrate, tartrate, phosphate and fluoride.     

N,N'-diphenyldithiomalonamide as a gravimetric reagent for nickel and cobalt

N,N'-Diphenyldithiomalonamide, (C₆H₆. NH. CS)₂CH₂, is found to be a very suitable gravimetric reagent for nickel(II) and cobalt(II). The complexes, of composition Ni(C₁₅H₁₃N₂S₂)₂ and Co(C₁₅H₁₃N₂S₂)₃, are stable and can be weighed after drying at 110°. Separation from base metals has been studied, and the structural interpretation is supported by DTA, TG, infrared and NMR data.     

Alizarin blue as a specific reagent for the gravimetric determination of copper

A new method for the gravimetric determination of copper was developed, based on the specific precipitation of copper alizarin blue from highly acid solutions. The determination can be carried out in very dilute solutions up to an amount of 2 mg of Cu. Copper can also be determined in alkali cyanide solution after demasking with formaldehyde.     

Benzeneacetaldehyde-4-hydroxy-alpha-oxo-aldoxime as a new analytical reagent for the spectrophotometric determination of cobalt

Benzeneacetaldehyde-4-hydroxy-α-oxo-aldoxime is proposed as a new sensitive and selective reagent for the spectrophotometric determination of cobalt. The reagent reacts with cobalt in the pH range 8.6–9.4 to form a yellow colored 1:3 chelate which is very well extracted in chloroform. Beer's law is obeyed in the concentration range 0.05–1.3 μg ml⁻¹ cobalt. The molar absorptivity of the extracted species is 2.746×10⁴ l mol⁻¹ cm⁻¹ at 390 nm. The proposed method is highly sensitive, selective, simple, rapid, accurate and has been satisfactorily applied for the determination of cobalt in synthetic mixtures, pharmaceutical samples, biological samples and alloys.     

Oximidobenzotetronic acid — a sensitive spot test reagent for iron(II), cobalt(II) and copper(II)

Summary Oximidobenzotetronic acid is suggested as a sensitive spot test reagent for iron(II), cobalt(II) and copper(II) in the presence of commonly occuring cations.

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Zusammenfassung Oximidobenzotetronsäure (3-Ntroso-4-hydroxycumarin) wird als empfindliches Tüpfelreagens zum Nachweis von Fe(II), Co(II) und Cu(II) in Gegenwart anderer Kationen vorgeschlagen.

     

2,2′-Diquinolyl ketoxime: A new reagent for the spectrophotometric determination of cobalt

Summary The synthesis of 2,2-diquinolyl ketoxime and its application to the spectrophotometric determination of cobalt is described. The effects due to p_H, time, solvents, reagent concentration and diverse ions are reported. Beer's law is obeyed and the molar extinction coefficient is 5.3 · 10⁴ at 365 nm.

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Zusammenfassung Die Synthese von 2,2-Dichinolylketoxim und dessen Verwendung zur spektrophotometrischen Bestimmung von Kobalt wurde beschrieben. Der Einfluß von pH, Zeit, Lösungsmitteln, Reagenskonzentration und verschiedenen Fremdionen wurden untersucht. Das Beersche Gesetz ist gültig; der molare Extinktionskoeffizient beträgt bei 365 nm 5,3 · 10⁴.

     

Tungstophosphoric acid as a new reagent for the spectrophotometric determination of phenothiazines

A simple and rapid spectrophotometric method for the determination of phenothiazines based on the formation of a colored compound between tungstophosphoric acid and phenothiazines is described. The proposed method is successfully employed for the determination of phenothiazine drugs in various pharmaceutical products.     

N-Acetylacetone-anthranilic acid as a gravimetric reagent for copper(II)

N-Acetylacetone-anthranilic acid has been employed as a reagent for the gravimetric determination of copper(II). The solid copper(II) chelate formed possesses 1:1 metal-ligand stoichiometry and is found to exist as an unsolvated dimer. The complex has a magnetic moment of 1.88 B.M. at 298 K. A non-planar dimeric structure is suggested to explain the observed facts.     

Quinolinic acid as a reagent for the gravimetric and volumetric estimation of palladium

Summary Like -amino-picolinic acid, quinolinic acid behaves as a highly selective reagent for palladium with which it forms a complex of composition Pd(C₇H₄O₄N)₂. The complex being very stable is precipitated from solutions with an acidity of 0.25 N to a maximum p_H of 2.1 and thus is separated from all the common ions and other platinum metals except copper which, however, can be kept in solution in presence of EDTA. The palladium complex is either weighed after drying or dissolved in a standard potassium cyanide solution which is later back titrated with silver nitrate solution.     

Dehydroacetic acid as a reagent for the separation and gravimetric determination of copper(II), aluminium and beryllium

Dehydroacetic acid is proposed as a reagent for the gravimetric determination of copper(II), aluminium and beryllium at pH 3.0-6.0, 3.0-6.0 and 7.5-9.5 respectively. Copper is weighed as the complex Cu(C(8)H(7)O(4))(2). Aluminium and beryllium are weighed as Al(2)O(8) and BeO. The reagent is easy to prepare.     

Study of 2-(2-quinolinylazo)-5-dimethylaminobenzoic acid as a new chromogenic reagent for the spectrophotometric determination of cobalt

2-(2-Quinolinylazo)-5-dimethylaminobenzoic acid (QADMAB) is proposed as a new sensitive and selective chromogenic reagent for spectrophotometric determination of cobalt. The QADMAB reacts with cobalt in the presence of cetyl trimethylammonium bromide (CTMAB) medium to form a violet complex of molar ratio 1:2 (cobalt to QADMAB) in the pH range 3.2-5.2. The molar absorptivity of the complex is 1.28x10(5) L mol(-1) cm(-1) at 625 nm. Beer's law is obeyed in range 0.01-0.32 micro g mL(-1). The relative standard deviation for eleven replicate samples of 0.2 micro g mL(-1) is 0.76%. This method was applied to the determination of cobalt in biological samples, Vitamin B(12), alloys and water with good results.     

用TPAC重量法测定钽的新方法

研究了TPAC作为沉淀剂用重量法测定含铌复杂基体中钽的可能性. 结果表明,TPAFTa经分解定量地转化为五氧化二钽, 并以此为称量形式. 对20多种共存离子的吸附或共沉淀的杂以质量均小于万分之四. 随着老化时间的增加晶体明显增大, 吸附或共沉淀的杂质显著减少. 选择了最佳实验条件、详细研究了TPAFTa的物理化学性质. 钽的回收率为98.1-101.8%、镍基高温合金试样分析结果为1.80±0.027%, 可认为TPAC是钽的特效沉淀剂.     

Trichlorophenoxyacetic acid as a reagent for the determination of Thorium

2:4:5-trichlorophenoxyacetic acid has been successfully used for the determination of thorium. It has been proved to a better reagent for thorium than 2:4-dichlorophenoxyacetic acid as it produces quantitative precipitation of thorium at a considerably lower pH value and can separate Th from a number of common elements, such as Ca, Ba, Sr, Zn, Co, Ni, Ti, U, etc. and cerite earths more effectively. Zr and Fe interfere, but iron may be removed by a convenient method. Direct weighing may be applicable for the estimation of thorium within the limites of experimental error,     

New gravimetric method for cobalt

A new gravimetric method for the determination of cobalt is described, based on precipitation from acidic solution with a reagent prepared by heating alpha-nitroso-beta-naphthol in a mixture of glacial acetic acid, hydrogen peroxide and syrupy phosphoric acid. The cobalt is weighed, after ignition of the precipitate, as Co(3)O(4). Iron(III), copper, chromium(III), vanadium(V), tungsten(VI), aluminium, molybdenum, nickel, titanium, zirconium, uranium(VI) and cerium do not interfere.     

2-Aminobenzothiazole as a gravimetric reagent: Milligram level determination of mercury(II)

Summary 2-Aminobenzothiazole has been used as a gravimetric reagent for the determination of Hg(II) at the milligram level. The interference of Pd(II) and V(V) can be suppressed by oxalate. Ag(I) and Au(III) interfere.

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Zusammenfassung 2-Aminobenzothiazol dient als Fällungsreagens für die gravimetrische Bestimmung von Hg(II) im Milligrammaßstab. Die Störung von Pd(II) und V(V) kann mit Oxalat behoben werden. Ag und Au(III) stören jedoch.

     

Neotetrazolium chloride: a new reagent for spectrophotometric determination of manganese

The interaction of Mn(VII) and the Neotetrazolium chloride has been examined. The ion-associate formed is extracted into 1,2di-chloroethane. The optimum conditions have been established. The molar absorptivity of the complex is (9.1+/-0.08)x10(5) l mol(-1) cm(-1). The sensitivity of the method is 6.04x1010(-5) mug cm(-2). It is possible to extract and determine manganese in the presence of large number of cations and anions. The characteristic values for the extraction and the aqueous phase equilibria were determined: extraction constant K(ex)=3.21x10(9), distribution constant K(D)=33 and association constant beta=9.72x10(7). The method is applicable to analysis of soils and steels.     

Thenoyltrifluoroacetone as a reagent for cobalt

Summary An indirect method is proposed for the determination of cobalt (II) with 2-thenoyltrifluoroacetone at the milligram level. The orange cobalt-TTA chelate can be quantitatively precipitated over the p_H range 4.0–8.0. It is dissolved in acid and estimated as cobalt sulphate. Cobalt(II) can be estimated in presence of silver, mercury(II), strontium, iron(III), chromium (III), thorium, zirconium, uranium, citrate and tartrate. The method is reproducible to within ±1 per cent.