Spectrophotometric determination of ruthenium

Zusammenfassung Es wurde festgestellt, daß die Mehrzahl der Amidoxime mit folgenden Ionen reagiert: Hg²⁺, Cu²⁺, Fe³⁺, Co²⁺, UO₂ ²⁺, Cd²⁺, Ag^+;, Pb²⁺, Pd²⁺, Ni²⁺. Von den Malonsäure-bis-amidoximen wurden hergestellt die Silber-, Blei-, Cadmium-, Kupfer- und zwei Quecksilbersalze, von den Amidoximen der Nicotin- und Isonicotinsäure Palladium-, Kupfer-, Cadmium- und Bleisalze. Die Salzbildungsfähigkeit der Amidoximgruppe ist vom Radikal, von den Substituenten an der Amidgruppe und vom Reagens-medium abhängig. Die braunrote Färbung mit Fe³⁺-Ionen ist für alle Amidoxime typisch, diese Reaktion kann zum Nachweis der am Amidstickstoff nichtsubstituierten Amidoxime angewandt werden.IX. Mitteilung: Collect. czechoslov. chem. Commun. 24, 1720 (1959). — X. Mitteilung: Collect. czechoslov. chem. Commun. (im Druck).     

Spectrophotometric determination of ruthenium with diphenylthiovioluric acid

Diphenylthiovioluric acid (DPHTVA) reacts with ruthenium(III) to form a complex which has an absorbance maximum at 520 nm. Effects of pH, heating time, buffer and reagent have been studied. DPHTVA has been found to be a sensitive reagent for ruthenium(III) (sensitivity = 0.0044 μg Ru/cm² for log I₀/I = 0.001), and has been made selective by the use of masking agents. The composition of the complex as revealed by different methods is 1:2 (ruthenium:DPHTVA).     

Spectrophotometric determination of ruthenium with 8-quinolinol

A spectrophotometric method is described for the determination of 2–80 μg of ruthenium. The method involves oxidation of ruthenium to ruthenate, addition of 8-quinolinol, adjustment of the pH to 4–6.5, digestion of the complex formed at 85° for 30 min, extraction with chloroform, and measurement of absorbance at 430 nm. Almost all other metals and excess of reagent are removed by washing the extract. About 98 % of ¹⁰⁶Ru tracer was recovered.     

Spectrophotometric determination of ruthenium with 3,4-diaminobenzoic acid

Ruthenium(III) chloride and 3,4-diaminobenzoic acid, in aqueous solution at pH 4.0-4.5, react slowly at room temperature, but more rapidly when the mixture is heated, giving solutions that go through colour transitions from amber to purple-red; maximum absorbance of fully developed solutions occurs at 550 nm. The effects of heating temperature and time, pH, reagent concentration, and other variables have been studied. The system conforms to Beer's law; optimum concentration range, for measurement in 10-mm cells, is about 0.5-2 ppm of ruthenium. Interference from foreign ions, especially other platinum elements, is avoided by a distillation separation of ruthenium. The spectrophotometric mole-ratio and continuous-variation methods indicated the presence of complexes of 1:2 and 1:3 ruthenium-to-reagent stoichiometry. Elemental analysis of solid products isolated from solution confirmed the 1:2 reaction ratio. Several other o-diamines gave similar coloured solutions and reaction stoichiometry.     

Spectrophotometric determination of germaniun with phenylflurorone after benzyl alcohol extraction

A procedure has been developed for the determination of traces of germanium with phenylflourone using benzyl alcohol extraction. The procedure is very sensitive, the molar extinction having a value of 144.700. The concentration of germanium in the organic phase should be between 0.05 and 0.5μ ml.     

Spectrophotometric determination of hydrogen peroxide after extraction with ethyl acetate

Hydrogen peroxide (1 × 10^?5?3 × 10^?3 mol dm^?3) is extracted from aqueous solution with ethyl acetate and back-extracted into titanium (IV) sulphate solution, then the absorbance is measured at 407 nm. This procedure can be applied in the presence of a variety of species which interfere with the conventional spectrophotometric method, and to highly coloured samples.     

Spectrophotometric determination of ruthenium and osmium

The optimum conditions for preparation of stable solutions of ruthenate and osmate, after alkaline fusion of ruthenium(IV) compounds, ruthenium metal and osmium metal in a silver crucible, have been determined. The molar absorptivities of ruthenate and osmate are 1.74 × 10³ 1. mole⁻¹.cm⁻¹ at 465 nm (Ru) and 2.75 × 10³ 1.mole⁻¹.cm⁻¹ at 340 nm (Os) in 2M sodium hydroxide. A differential spectrophotometric method has been developed for determination of ruthenium in ruthenium dioxide, lead ruthenite and bismuth pyroruthenate. Simultaneous spectrophotometric determination is proposed for ruthenium and osmium. The other platinum metals interfere seriously only when present in> 1:1 w/w ratio to Ru.     

Spectrophotometric determination of platinum in glass after extraction with polyurethane foam

A spectrophotometric method has been developed for determination of trace amounts of platinum in glass. The method is based on the extraction of platinum(II) from 1M hydrochloric acid containing 0.2M stannous chloride and 4 x 10(-4)M dithizone onto polyurethane foam, elution with acetone (containing 3% v/v concentrated hydrochloric acid) and measurement of the absorbance of the eluate at 530 nm. Beer's law is obeyed up to 10.0 microg/ml Pt. The minimum platinum level in the eluate that can be determined by this method is 0.1 microg/ml.     

Spectrophotometric determination of some dibenzazepines with picryl chloride

A simple and sensitive spectrophotometric method has been developed for the determination of some dibenzazepines, based on reaction with picryl chloride in chloroform medium and measurement at 395 nm. Beer's law is obeyed in concentration ranges 0.1-1.0 microg/ml for imipramine hydrochloride, trimipramine maleate and opipramol dihydrochloride, 0.16-1.6 microg/ml for desipramine hydrochloride and 0.4-2.4 microg/ml for clomipramine hydrochloride. The method was applied successfully to the determination of dibenzazepines in tablets and the results were comparable to those obtained by official procedures.     

Spectrophotometric determination of chloride in plants

This indirect spectrophotometric determination of chloride in plants is based on displacement of thiocyanate from mercury(II) thiocyanate. Thiocyanate is extracted into nitrobenzene as tris(l,10-phenanthroline)iron(II) thiocyanate for measurement at 516 nm. Accuracy and precision are similar to those of the Volhard method but only about 2–200 mg samples are needed.     

Spectrophotometric determination of traces of zinc in high-purity solders after extraction with tri-n-octylamine

Summary A simple and sensitive method is described for separation and spectrophotometric determination of trace amounts of zinc in high-purity solders. The bulk of the matrix elements is eliminated, the lead by precipitation as chloride, the rest by cupferron extraction into chloroform. The extraction of the anionic zinc chloro-complexes with tri-n-octylamine into benzene effectively separates zinc at as low a level as 0.001% in the solder. Zinc is stripped with 0.5M sodium hydroxide and the last traces of other metals are masked with tartaric acid. 4-(2-Pyridylazo)resorcinol is used as the spectrophotometric reagent. The relative standard deviation is about 8%.

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Spektrophotometrische Bestimmung von Zinkspuren in reinstem Lötmittel nach Extraktion mit Tri-n-oktylamin

Zusammenfassung Es wird eine einfache und empfindliche Methode für die Trennung und spektralphotometrische Bestimmung von Spurenmengen von Zink in reinstem Lötmittel beschrieben. Die Hauptmenge der Grundelemente wird mit Cupferron/Chloroform extrahiert. Die Extraktion der anionischen Zink- Chlorokomplexe mit Tri-n-octylamin/Benzol trennt Zinkmengen von der Größenordnung von 0,001% im Lötmittel. Die Rückextraktion des Zinks in die wäßrige Phase erfolgt mit einer 0,5M Natriumhydroxid-Lösung; die letzten Spuren anderer Metalle werden mit Weinsäure maskiert. Als spektrophotometrisches Reagens wird 4-(2-Pyridylazo)-resorcinol (PAR) benützt. Die relative Standardabweichung beträgt etwa 8%.

     

Spectrophotometric determination of carbon monoxide with ruthenium(II) octaethylporphyrin

A novel spectrophotometric method for the estimation of carbon monoxide at levels from 2 to 250 ppm is presented. The method is empirical and based on formation of a carbonyl complex of ruthenium(II) octaethylporphyrin and measurement of the difference in absorbance at 393.5 nm between this complex and the porphyrin reagent. Oxygen and nitrogen do not interfere and up to 300 ppm of sulphur dioxide and about 1500 ppm of carbon dioxide can be tolerated in determination of carbon monoxide at the 4 and 10 ppm levels. Hydrogen sulphide interferes and must be removed before the determination. The method has been tested over the range 2-45 ppm of carbon monoxide with 16 synthetic and 2 commercial standard air samples. The average error was +/- 3%. Application to urban-air samples and car-exhaust gases yielded acceptable results. The main disadvantages are the tedious preparation of the initial ruthenium(III)-porphyrin compound and the decomposition of the reagent in the presence of hydrazine.     

Spectrophotometric determination of mercury in soils with triphenyltetrazolium chloride

The formation of the acidocomplex of mercury(II) with triphenyl-tetrazolium chloride is studied spectrophotometrically in water-organic media. The composition of the complex is established as TTC:Hg:I = 1:1:1. The molar absorptivity (255) = (6.45 +/- 0.12) x 10(4) 1 mole(-1). cm(-1) is determined. The selectivity of the reaction is studied and the method for determination of mercury(II) 0.1-0.8 mug/ml is shown. Extraction investigations of the system discussed were carried out. The characteristic values for the extraction equilibrium and the equilibrium in the aqueous phase was determined: extraction constant K(ex) = 3.16 x 10(4), distribution constant K(D) = 20.67, and association constant = 1.53 x 10(3). 5 A rapid and sensitive extractive-photometric method for determination of mercury(II) in soil was developed. The determination was carried out without preliminary elimination of mercury.