Solochrome Black P.V. as a new reagent in chelatometry

Summary Solochrome Black P.V. has proved to be a suitable metallochromic indicator in direct titrations of Mg, Zn, Cd and Mn^II with EDTA or in back titrating Pb, M and Co at p_H 10. By its aid together with the application of masking agents as potassium cyanide and ammonium fluoride and the mercuric nitrate procedure, fifteen binary mixtures were analysed using simple procedures which gave precise, reproducible and highly accurate results. It can be used as a substitute for Eriochrome Black T in determining micro and milligram amounts of the above mentioned cations.Part I: Khalifa, H., and S. W. Bishra: Z. analyt. Chem. 183, 108 (1961).     

Solochrome Black P. V. as a new reagent in chelatometry

Summary Solochrome Black P. V. with its distinct acid-base properties has proved to be a suitable reagent for the spectrophotometric microdetermination of magnesium either alone or in the presence of zinc, calcium, cobalt, or copper. Interference due to many cations is simply eliminated. Spectrophotometric titration of magnesium with EDTA is investigated. Sensitivity of the method allows determining of 0.05 to 3 ppm Mg with reasonable accuracy.

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Zusammenfassung Solochromschwarz P. V., das als Säure-Base-Indicator verwendet werden kann, ist auch ein geeignetes Reagens zur spektrophotometrischen Mikrobestimmung von Magnesium. Zink, Calcium, Kobalt, Kupfer und andere Kationen können in einfacher Weise maskiert werden. Die spektrophotometrische Titration des Magnesiums mit ÄDTA-Lösung wird ebenfalls untersucht. 0,05–3 ppm Mg können mit guter Genauigkeit bestimmt werden.

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Part II:Khalifa, H., and M. M.Khater: Z. analyt. Chem.183, 241 (1961).     

Solochrome Black P.V. as a new reagent in chelatometry

Summary The acid-base properties of Solochrome Black P.V. have been studied with the object of applying it as a metallochromic or as a chromophoric indicator. The pK values of 4.1, 7.0 and 11 corresponding to the three steps of ionisation of the free acid were evaluated by aid of the relation between log (acid)/(salt) and p_H values obtained during the course of the potentiometric titration of the free acid with a free base together with the E-p_H relation. The molecular ratio of the magnesium-dye chelate and its mode of chelation are given.

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Zusammenfassung Die Eigenschaften des Farbstoffs Solochrome Black P.V. werden im Hinblick auf seine Verwendung als Metalloder Farbindicator untersucht. Entsprechend den drei Dissoziationsstufen der freien Säure werden pK-Werte von 4,1, 7,0 und 11 gefunden. Diese werden mit Hilfe der Beziehungen zwischen log [Säure]/[Salz] und p_H sowie zwischen E und p_H ausgewertet. Bildung und Zusammensetzung des Mg-Farbstoffchelats werden näher untersucht.

     

Solochrome violet R.S. as a new colorimetric reagent

Summary Solochrome violet R.S. has proved to be a sensitive colorimetric reagent for the microdetermination of vanadium in the limits of 0.05 to 6 ppm with a sensitive filter photometer or a spectrophotometer, at 580 nm. A large number of cations up to 100 fold the vanadium amount do not interfere with its determination. The present work comprises a comparative study on the behaviour of solochrome violet and Fast Grey, based upon the great similarity in the molecular structure of the two dyes and the influence of the orthonitrophenolic group in the molecule of Fast Grey.Part I: See Z. analyt. Chem. 178, 184 (1960).     

Solochrome Violett R. S. as a new colorimetric reagent

Summary The reaction between molybdenum and the sulphonic acid azo dye Solochrome Violet R.S. has proved to be a suitable one for the microdetermination of Mo amounts covering the range of 0.3 to 10 ppm in purely aqueous solutions. The variation of extinction with concentration conforms satisfactorily with Beer's law throughout the whole range. Very many cations and anions do not interfere with such a determination. Ferric iron up to 2 mg per 25 ml is completely masked with ascorbic acid.Part II: Khalifa, H., and S. W. Bishara: Z. analyt. Chem. 178, 345 (1960).     

Tetrahydroxyazon SCl as a new analytical reagent for determining copper(II)

2,2′,3,4-Tetrahydroxy-3′-sulfo-5-chloroazobenzene was synthesized from pyrogallol and 2-aminophenol-5-chlorobenzenesulfonic acid. The complexation of copper(II) with this reagent was studied. A homoligand compound of the stoichiometry 1: 1 was obtained at pH 2. The optimum conditions for complexation were found and the equilibrium constant of the reaction was calculated. The selectivity of the reaction was studied and the stability constant of the complex was evaluated. Procedures were developed for the photometric determination of copper in alloys and soils.     

Synthesis and analytical application of tribromocarboxyarsenazo as a new chromogenic reagent for zirconium

A new chromogenic reagent tribromocarboxyarsenazo has been synthesized and the chromogenic reaction of this reagent with zirconium studied. In the medium of 0.5 mol/1 HCl, a blue complex is formed by the reaction of zirconium with tribromocarboxyarsenazo. The maximum absorption of the complex is at 633 nm, and the apparent molar absorptivity is 4.8 x 10(4) 1/mol/cm. Beer's law is obeyed over the zirconium concentration range 0-18, mug/25 ml. The method has been applied to the determination of zirconium in aluminum, copper and magnesium alloys with satisfactory results.     

Bismuthiol as an analytical reagent

Summary Lead can be determined from its Bismuthiol II complex volumetrically by dissolving it in an excess of EDTA at a p_H of about 10 and titrating the excess of the EDTA against a magnesium or lead solution. In the same way silver can be determined by dissolving the complex in an excess of cyanide and back titrating the excess against a standard silver nitrate with iodide as the indicator. The results of the former are fairly accurate while those due to latter are highly satisfactory with silver less than 20 mg. With higher amounts of silver, however, the results are within +2%.Part VIII see Z. analyt. Chem. 156, 103 (1957).     

Nicotinamidoxime as an analytical reagent

Summary Cobalt(II) gives a deep blue colour with nicotinamidoxime in alkaline aqueous-ethylalcoholic medium which has been used with advantage for the spectrophotometric determination of this metal. The optimum p_H for the development of colour is 9.8–11.3 in aqueous-alcoholic (40% v./v.) medium in presence of a large excess of the reagent, at 15–40°C. The colour intensity is measured at 580 m,. Sensitivity is 0.01 g cobalt per cm², while visual identification limit is 0.5 g cobalt per ml (12·10⁶). Beer's law is obeyed in the range of 0.2–20 ppm of the metal, with an optimum range of 2–16 ppm. The colour is stable for about half an hour in the p_N range of 9.8–11.3 and at least one hour in the range of 10.5 to 11.0. On account of the high p_N and alcoholic medium used, most of the cations and anions interfere and, hence, must be removed.Part I: See Z. anal. Chem. 168, 326 (1959).     

Bis-salicylaldehyde-ethylenediamine as an analytical reagent

Summary The compound bis-salicylaldehyde-ethylenediamine was prepared by the condensation of salicylaldehyde with ethylenediamine. It was crystalline and quite stable. The solution of the compound in caustic alkali was used for the analytical reactions of various ions. Ions of Cu²⁺, Ni²⁺, Bi³⁺, Zn²⁺, Hg²⁺, Sb³⁺, Sn²⁺ and Ce⁴⁺ formed precipitates, while those of As³⁺ and Pd²⁺ gave slight turbidity and Fe²⁺, Pe³⁺, Co²⁺ gave colour reactions. Rest of the ions did not respond towards the reagent. The sensitivity of the reactions for Cu²⁺, Ni²⁺, Fe²⁺, Fe³⁺, Ce⁴⁺, Co²⁺ and Sb³⁺ was high and their quantitative determinations are possible.

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Zusammenfassung Die Verbindung Bis-salicylaldehyd-äthylendiamin wurde durch Kondensation von Salicylaldehyd mit Äthylendiamin dargestellt. Sie ist kristallin und durchaus stabil. Die ätzalkalische Läsung dieser Verbindung wird zu analytischen Reaktionen mit verschiedenen Ionen benutzt. Die Ionen Cu²⁺, Ni²⁺, Bi³⁺, Zn²⁺, Hg²⁺, Sb³⁺, Sn²⁺ und Ce⁴⁺ ergeben Niederschläge, As³⁺ und Pd²⁺ geben eine geringe Trübung und Fe²⁺, Fe³⁺ sowie Co²⁺ liefern Farbreaktionen. Die übrigen Ionen sprechen auf das Reagens nicht an. Die Empfindlichkeit der Reaktionen mit Cu²⁺, Ni²⁺, Fe²⁺, Fe³⁺, Ce⁴⁺, Co²⁺ und Sb³⁺ ist groß und eine quantitative Bestimmung dieser Ionen ist möglich.

     

Nicotinamidoxime as an analytical reagent

Summary Uranium (VI) has been found to give a yellow colour with nicotinamidoxime in alkaline medium which is highly satisfactory for the spectrophotometric estimation of the metal. The optimumph for development of the colour is 10.9–11.5 in presence of a large excess of the reagent, at 10–40C. The colour intensity is measured at 400 m. Sensitivity is 0.045 g uranium per cm², with a visual identification limit of 5 g uranium per ml. Beer's law is obeyed in the range of 5–40 ppm of the metal with an optimum range of 8–40 ppm. The colour is stable for at least one hour. All the common anions are without effect, excepting however, phosphate, carbonate, and cyanide which are tolerated only in traces. Use of tartrate or EDTA helps to mask effectively all the interfering cations excepting copper, iron and vanadium.     

Bis-salicylaldehyde-ethylenediamine as an analytical reagent

Summary Copper has been determined gravimetrically as its bis-salicylaldehyde-ethylenediamine complex of the composition C₁₆H₁₄O₂N₂ · Cu, dried at 100–120° C. The complex is completely precipitated in theph range of 10.5–13.5, adjusted with ammonia or caustic alkali. It is stable in presence of excess ammonia, 0.1 N alkali, ammonium salts and complexing agents as tartrate, citrate, sodium-thiosulphate, fluoride, thiourea, triethanolamine and EDTA. In presence of tartrate and ammonia the ions of alkali metals, alkaline earths, Ag⁺, Tl⁺, Tl³⁺, Pb²⁺, Cd²⁺, Co²⁺, Mn²⁺, Pd²⁺, Al³⁺, Cr³⁺, La³⁺, Ce³⁺, Au³⁺, Pt⁴⁺, Ti⁴⁺, Zr⁴⁺, Th⁴⁺, UO₂ ²⁺ and anions as VO₃ ^–, MoO₄ ^2–, WO₄ ^2–, CrO₄ ^2–, PO₄ ^3–, AsO₄ ^3– do not interfere. Ni²⁺ and Hg²⁺ are masked by tartrate, EDTA and ammonia; As³⁺, Sb³⁺ and Sn²⁺ are separated using fluoride as the complexing agent; at an alkalinity of 0.1 N caustic alkali in presence of tartrate As³⁺, Sb³⁺, Sn²⁺, Bi³⁺, Zn²⁺ and Fe³⁺ are separated. Fe³⁺ can also be separated using triethanolamine as the masking agent at aph of about 13.0. Copper can be separated from almost all the ions, thus affording a highly selective method for the determination of copper.

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Zusammenfassung Es wird eine gravimetrische Methode zur Bestimmung von Kupfer beschrieben, die auf der Bildung des Bis-salicylaldehyd-äthylendiaminkomplexes beruht. Dieser hat die Zusammensetzung C₁₆H₁₄O₂N₂ · Cu. Die Fällung wird imph-Bereich 10,5–13,5 (mit Ammoniak oder Alkalilauge eingestellt) vorgenommen und der Niederschlag bei 100°–120° C getrocknet. Der Komplex ist beständig in Gegenwart von überschüssigem Ammoniak, 0,1 n Alkali, Ammoniumsalzen sowie Tartrat, Citrat, Natriumthiosulfat, Fluorid, Thioharnstoff, Triäthanolamin und ÄDTA. In Gegenwart von Tartrat und Ammoniak stören nicht: Alkalien, Erdalkalien, Ag⁺, Tl⁺, Tl³⁺, Pb²⁺, Cd²⁺, Co²⁺, Mn²⁺, Pd²⁺, Al³⁺, Cr³⁺, La³⁺, Ce³⁺, Au³⁺, Pt⁴⁺, Ti⁴⁺, Zr⁴⁺, Th⁴⁺, UO₂ ²⁺ sowie VO₃ ^–, MoO₄ ^2–, WO₄ ^2–, CrO₄ ^2–, PO₄ ^3– und AsO₄ ³⁺. Ni²⁺ und Hg²⁺ können mit Tartrat, ÄDTA und Ammoniak maskiert werden, As³⁺, Sb³⁺ und Sn²⁺ mit Fluorid. In 0,1 n ätzalkalischer Lösung in Gegenwart von Tartrat können As³⁺, Sb³⁺, Sn²⁺, Bi³⁺, Zn²⁺ und Fe³⁺ abgetrennt werden. Fe³⁺ kann ebenfalls mit Triäthanolamin beiph 13,0 maskiert werden. Das beschriebene Verfahren erlaubt somit eine Abtrennung des Kupfers von fast allen anderen Ionen.

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Part I: Singh, B. R., and S. Kumar: Z. analyt. Chem. 185, 211 (1962).     

Isonitrosoacetanilide as an analytical reagent

In a continuation of earlier work on the reactivity of various isonitrosoacetarylides, the simplest of the series, isonitrosoacetanilide was examined. In acidic medium, this reagent gives a specific reaction with palladium (dilution limit 1:400,000), and in ammoniacal medium a very sensitive reaction with cobalt (dilution limit 1:1,000,000). The composition of the complexes involved was established as R₂Pd and R₃Co₂. The effect of substitution on the reactivity is discussed.     

Nicotinamidoxime as an analytical reagent

Summary Alkaline solutions of nicotinamidoxime containing traces of nickel(II) give a deep blue color on treatment with iodine. At a p_H of 10.5–11.5 in presence of an excess of the amidoxime the color develops almost instantaneously and is stable for at least 24 hrs. The system adheres to Beer's law in the range of 0.3–10 ppm of nickel, and the optimum range for measurement (1 cm cell) is 3–10 ppm of the metal. The color reaction is highly sensitive (spectrophotometric: 0.014 g Ni cm^–2 at 575 nm identification limit: 0.5 g Ni ml^–1; 12 · 10⁶).All the common anions are without any effect excepting CN^– and EDTA which interfere seriously. Interference of Pb²⁺, Bi³⁺, Al³⁺, Ti⁴⁺, Zr⁴⁺ and Th⁴⁺ can be masked by excess tartrate; while in the presence of Cu²⁺, Co²⁺, Zn²⁺, Mn²⁺ and Fe³⁺, the Ni²⁺ is first separated by the anion exchange method of Kraus and Moore ³ and then determined as usual.From the results of polarographic investigations it has been concluded that in alkaline medium nicotinamidoxime is first oxidized possibly to an azo type of compound which interacts with nickel(II) forming the deep blue color.Part II: K. K. Tripathi and D. Banarjea: Z. analyt. Chem. 168, 407 (1959).     

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.     

Diphenic acid as an analytical reagent

Summary Diphenic acid behaves as a selective reagent for the estimation of thorium in presence of phosphate, arsenate, molybdate, alkaline, earths, copper, cadmium, lead, bismuth, tin, aluminium, chromium, nickel, cobalt, zinc, manganese, magnesium and palladium. Thorium can be successfully separated from the cerite earths by the reagent from solutions having thoria: earth oxide ratio 126 by single precipitation and by double precipitation when the above ratio is 144. The reagent can separate thorium from solutions having ThO₂U₃O₈ ratio upto 180 by double precipitation. The metal can also be recovered from monazite sands.Thanks are expressed hereby to Dr. A. K. Ghosal, Principal, Darjeeling Government College and Dr. A. K. Mukherjee of Indian Association for the Cultivation of Science, Calcutta, for their kind encouragement and to the Government of India, Ministry of Natural Resources and Scientific Research for a gift of Indian Monazite for analysis.     

Bismuthiol II as an analytical reagent

Summary The reagent Bismuthiol II completely precipitates palladium at a maximum acidity of 0.3 N in nitric acid, 0.5 N in hydrochloric acid or 1 N in sulphuric acid and also at a maximum p_H of about 8.0. The palladium complex Pd (C₈H₅N₂S₃)₂ is stable even up to a temperature of about 250° C. From a mineral acid solution palladium can be estimated in presence of ions of Fe²⁺, Al, Cr, Th, Ce³⁺, Zr, Ti⁴⁺, UO₂ ²⁺, Be, Mn, Co, Ni, Mg, P0₄ ^3–, AsO₄ ^3–, rare earths, alkalis, alkaline earths, Ce⁴⁺, WO₄ ^2– and MoO₄ ^2– that are not ordinarily precipitated by the reagent. At a p_H of 4.75 to 8.2, EDTA, Na-salt, keeps in solution, besides the above ions, the ions of Tl+, Cu²⁺, Pb, Bi³⁺, As³⁺, Sb³⁺, Zn, Cd, Fe³⁺, CrO₄ ^2–, AsO₃ ^3– and VO₃ ^–. Tartrate, however, at a p_H 6.2–8, keeps all the ions including Sn⁴⁺ in solution except of course Tl⁺, Cu²⁺, Pb and Cd. Separation from Ce⁴⁺, WO₄ ^2–, MoO₄ ^2– and AsO₄ ^3– at a low p_H require the presence of tartrate. Ag⁺, Hg²⁺ and also Pb may be complexed with potassium iodide at a p_H 6–8. Tl⁺ and Ag⁺ may also be separated in presence of cyanide in an acetate buffer when palladium remains in solution and from which it may be re-precipitated by acidification.Part II see Z. analyt. Chem. 154, 413 (1957).     

Bismuthiol II as an analytical reagent

Summary With copper, bismuthiol II forms both cuprous and cupric complexes which are stable in mineral acids, acetic, citric and tartaric acids and the cuprous complex compared to cupric is insoluble in EDTA solution as well in organic solvents. The melting points of both cupric and cuprous complexes are respectively 148° C and 198° C. As an insoluble cupric complex copper is estimated from solutions having a maximum acidity of 0.1 N in hydrochloric or sulphuric acid and of 0.5 N in acetic acid. Even at a lower acidity, up to a p_H of about 6.2, the precipitation of copper is quantitative but at a p_H higher than 6.2 the copper complex shows an increased solubility. By the proper control of p_H and by suitable masking agents, it is possible to separate copper from almost all the ions except palladium, cadmium, lead and thallous ions.Cuprous complex, being more stable and insoluble and having practically the same tolerance to an acid solution or to a solution at a high p_H, helps towards a more complete separation of copper from all the ions stated except the thallous and bismuth.Part IX: See Z. analyt. Chem. 156, 265 (1957).