Spectrophotometric and first-derivative spectrophotometric determination of cadmium witho-hydroxybenzenediazoaminoazobenzene (HDAA)

The synthesis ofo-hydroxybenzenediazoaminoazobenzene (HDAA) is described. Cadmium forms with HDAA in the presence of Triton X-100 a 13 complex, which gives a maximum absorption at 520nm with an apparent molar absorptivity of 1.97 × 10⁵1 · mol^–1 · cm^–1 in pH 10 borax buffer solution and 1.52 × 10⁵1 · mol^–1 · cm^–1 in ammoniacal medium. In both media, Beer's law is followed in the range of 0 –10 g of cadmium in 25ml of solution and the coefficients of variation do not exceed 1.5%. A derivative method has been employed to determine cadmium in certain waste water samples without separation.     

Highly sensitive spectrophotometric determination of micro amounts of iron with chromai blue G and cetyltrimethylammonium chloride

Summary A ternary complex between iron(III), Chromal Blue G (C. I. 43835) and cetyltrimethylammonium chloride is proposed for the determination of iron (III). The stoichiometric ratio of iron (III) to Chromai Blue G is 13. Beer's law is obeyed from 0.04 to 0.4 ppm of iron; the molar absorptivity is 1.43×10⁵ l·mole^–1·cm^–1. The proposed method has been applied to the determination of iron in a magnesium alloy.

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Hochempfindliche spektrophotometrische Bestimmung von Mikromengen Eisen mit Chromctlblau G und Cetyltrimethylammoniumcblorid

Zusammenfassung Zur Bestimmung von Eisen(III) wird ein ternärer Komplex aus Eisen(III), Chromai Blue G (Farbindex 43835) und Cetyltrimethylammoniumchlorid vorgeschlagen. Das stöchiometrische Verhältnis Eisen(III): Chromal Blue G ist 13. Das Beersche Gesetz gilt von 0,04 bis 0,4 ppm Fe; der Extinktionskoeffizient ist 1,43×10⁵ l·mole^–1·cm^–1. Die vorgeschlagene Methode dient für die Bestimmung von Eisen in Magnesiumlegierungen.

     

Spectrophotometric determination of uranium with 5-(2′-carboxyphenyl)azo-8-quinolinol in the non-ionic micellar medium of Triton X-100

Triton X-100, a non-ionic surfactant, has been used to sensitize the reaction of 5-(2-carboxyphenyl)azo-8-quinolinol with uranium in aqueous medium at pH 5.2–6.1 to form a wine red coloured complex. The micellar sensitization results in two and a half-times enhanced molar absorptivity enabling the determination of uranium in rock samples at ppm level, stability of the complex enhanced from 4 hours to at least 72 hours. Extraction of the complex is avoided making the procedure simple, rapid and easy in operation. The molar absorptivity and Sandell's sensitivity of the complex are 1.50·10⁴l·mol^–1·cm^–1 and 15.9 ng·cm^–2, respectively, at _max=568 nm. Beer's law is obeyed over the range 0–3.3 g·ml^–1 of uranium. An amount as low as 0.19 g·ml^–1 of uranium could be determined satisfactorily within a relative standard deviation of ±1.3%. The limits of determination and practical quantitation are 0.29 and 1.80 ppm, respectively. The method was applied to the determination of uranium in soil, stream sediment and rock samples.     

Spectrophotometric determination of uranium(VI) with 1-(2′-thiazolylazo)-2-naphthol in the presence of Trition X-100

Uranium(VI) reacts with 1-(2-thiazolylazo)-2-naphthol to form a red-coloured chelate in the pH range 5.3–7.2, maintained by 0.04 M acetate buffer. Absorbance of the sparingly soluble complex, solubilized and stabilized by Triton X-100, is measured after 30 min and it is stable for at least 16 hours. The complex exhibits maximum absorbance at 575 and 625–630 nm, but absorbance at longer wavelengths is not stable. The 12 complex obeys Beer's law over the concentration range 0.4–6.4 g of uranium(VI) per cm³, has molar absorptivity 3.36·10⁴ dm³·mol^–1·cm^–1, Sandell sensitivity 7.0 ng·cm^–2, formation constant (log K) 9.32 and coefficient of variation ±0.77%. Effect of 60 ions has been studied and selectivity improved considerably in presence of CDTA. The method has been applied for determination of uranium content in a rock sample.     

The chelation ofo-nitrosopyrimidinols. I

Summary A spectrophotometric study has been made on the iron-2,6-diamino-5-nitroso-4-pyrimidinol reaction. The study shows that the reaction ratio is 4 to 1 reagent to iron(II). The blue complex has an absorption maximum at 653 nm and a molar absorptivity of 2.0·10⁴ l.mole^–1.cm^–1.

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Zusammenfassung Die Reaktion von Eisen(II) mit 2,6-Diamino-5-nitroso-4-pyrimidinol wurde spektrophotometrisch untersucht. Die Komplexbildung findet im Molverhältnis Reagens: Eisen=41 statt. Der blaue Komplex hat ein Absorptionsmaximum bei 653 nm und eine molare Extinktion von 2,0·10⁴ l.Mol^–1.cm^–1.

     

Spectrophotometric determination of trace amounts of cadmium using Cd(II)-KI-Crystal violet system in the presence of triton X-100 and PVA

A new highly sensitive spectrophotometric method for determination traces of cadmium using Cd-(II)-KI-Crystal Violet system in the presence of Triton X-100-poly(vinyl) alcohol (PVA) mixture has been developed. The apparent molar absorptivity of the system is 1.77 × 10⁵ 1-mol^–1 cm^–1 and its Sandell's sensitivity is 6.35 × 10^–4 g·Cd·cm^2–. Beer's law is obeyed up to 0.32 g·Cd(II)·ml^–1. The method has been applied to determine Cd(II) in waste water, rice and pork meat samples with satisfactory results.     

Spectrophotometric determination of iron at the p. p. m. level in sugar samples with 2-nitroso-5-dimethylaminophenol

Summary Ppm amounts of iron in sugar samples were determined spectrophotometrically with 2-nitroso-5-dimethylaminophenol (nitroso-DMAP). The iron(II) complex formed with nitroso-DMAP, is stable in aqueous solution at about pH 9. The method is simple, rapid, selective and very sensitive (molar absorptivity: 4.0×l0⁴l-mol^–1-cm^–1).

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Zusammenfassung Ppm-Mengen Eisen in Zuckerproben wurden spektrophotometrisch mit Hilfe von 2-Nitroso-5-dimethylaminophenol (Nitroso-DMAP) bestimmt. Der Eisen(II)komplex mit Nitroso-DMAP ist in wäßriger Lösung bei pH9 beständig. Das Verfahren ist einfach, rasch, selektiv und sehr empfindlich (molare Extinktion: 4,0·10⁴ l·Mol^–1·cm^–1).

     

Photometric determination of palladium with 3-nitroso-2,6-pyridinediol

Summary A highly sensitive and selective photometric method has been developed for the determination of palladium. The method is based on the yellow complex (absorption maximum-430 run) formed when palladium and 3-nitroso-2,6-pyridinediol are heated together in 0.1M perchloric acid. The reaction ratio is 21 reagent to palladium. The molar absorptivity of the yellow complex is 2.6 · 10⁴ liter mole^–1 cm^–1. Only platinum (IV), ruthenium (III), and iron(III) seriously interfere among the common and platinum metals.

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Zusammenfassung Eine sehr empfindliche und selektive photometrische Methode zur Palladiumbestimmung wurde ausgearbeitet. Sie beruht auf dem gelben Komplex (Absorptionsmaximum bei 430 nm), der sich beim Erwärmen aus Palladium und 3-Nitroso-2,6-pyridindiol in 0,1-n Perchlorsäure bildet. Reagens und Metallion reagieren im Verhältnis 21. Die molare Absorption beträgt 2,6 · 10⁴ 1 mol^–1 cm^–1. Nur Platin(IV), Ruthenium(III) und Eisen(III) stören die Bestimmung.

     

Spectrophotometric determination of trace amounts of iron(III) by extraction of mixed-ligand iron-tartrate-purpurin or iron-NTA-purpurin complex

Summary Spectropbotometric Determination of Trace Amounts of Iron(III) by Extraction of Mixed-Ligand Iron-Tartrate-Purpurin or Iron-NTA-Purpurin Complex A selective method is described for the determination of microgram amounts of iron(III) by means of its reaction at pH 9.0 with purpurin (1,2,4-trihydroxyanthraquinone) and tartrate or NTA and extraction into methyl isobutyl ketone. The molar absorptivity of the 112 iron(III)-auxiliary ligand-purpurin complex is 4.8×10⁴ 1·mole^–1·cm^–1 at 595 nm. Beer's law is obeyed from 0.05 to 0.25 ppm of iron in the aqueous phase. Procedures for determination of iron in tartrate or NTA medium, and fluoride-tartrate-NTA medium are given. The method is suitable for determining iron in Zn metal, W metal, NTA, drinking water, wines, urine and tartrates.     

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])     

Photometric determination of ruthenium with 3-nitroso-2,6-pyridinediol

Summary A highly sensitive photometric method has been developed for the determination of ruthenium. The method is based on the purple colored complex formed when ruthenium is heated with 3-nitroso-2,6-pyridinediol (NPD) in slightly acidic solution. The molar absorptivity of the purple complex is 2.6 · 10⁴l.mole^–1,cm^–1. The reaction ratio is 31 reagent to ruthenium.

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Zusammenfassung Eine sehr empfindliche photometrische Methode zur Rutheniumbestimmung wurde ausgearbeitet. In schwach saurem Medium bildet Ruthenium beim Erhitzen mit 3-Nitroso-2,6-pyridindiol (NPD) einen purpurroten Komplex. Dessen molare Absorption beträgt 2,6 · 10⁴ l/Mol.cm. Reagens und Ruthenium reagieren im Verhältnis 31.

     

Sensitive spectrophotometric determination of tin with Pyrogallol Red and cetyldimethylbenzylammonium ions

Summary Tin(IV), in the presence of cetyldimethylbenzylammonium chloride (CDBA), forms with Pyrogallol Red (PR) a complex SnPR-CDBA. This complex floates at the interface between hexane and aqueous medium. It dissolves in acetone and can be advantageously used for the determination of tin. The molar absorptivity is 6.5×10⁴ l·mole^–1·cm^–1 at 480 nm. The method is selective when citric acid is used as masking agent. Phosphate, fluoride, EDTA, nitrite and sulphide interfere.

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Zusammenfassung Zinn(IV) bildet mit Pyrogallolrot (PR) in Gegenwart von Cetyldimethylbenzylammoniumchlorid (CDBA) einen Komplex. Dieser wird flotiert, in Aceton gelöst und zur Bestimmung von Zinn verwendet. Der molare Absorptionskoeffizient bei =480 nm beträgt =6,5·10⁴ l·mol^–1 cm^–1. Die Methode ist selektiv, wenn Zitrate zur Maskierung verwendet werden. Es stören Phosphat, Fluorid, ÄDTA, Nitrit und Sulfid.

     

Spectrophotometric determination of osmium using phenanthrenequinone monosemicarbazone (PQCS) as a sensitive and selective reagent

Summary The reddish brown complex formed by osmium(VIII) and phenanthrenequinone monosemicarbazone, has an absorption maximum at 500 nm with molar absorptivity of 1.85×10⁴ 1 cm^–1 mole^–1. This complex is used to determine 50–198g osmium(VIII) in 37 DMF-methanol medium. The pH range for the determination is 7.2–9.2. The limits of interference due to foreign ions have been studied.

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Spektrophotometrische Bestimmung von Osmium mit Phenanthrenchinon-Monosemicarbazon als empfindlichem und selektivem Reagens

Zusammenfassung Der aus Osmium(VIII) und Phenanthrenchinon-Monosemicarbazon entstehende rotbraune Komplex hat sein Absorptionsmaximum bei 500 nm. Die molare Extinktion beträgt 1,85×10⁴ l·cm^–1·Mol^–1. Dieser Komplex diente zur Bestimmung von 50–198g Osmium(VIII) in einer Lösung aus DMF und Methanol im Verhältnis 37. Das einzuhaltende pH liegt zwischen 7,2 und 9,2. Die Störungen durch Fremdionen wurden untersucht.

     

Spectrophotometric determination of iron in aluminium metal and some non-ferrous alloys

A new, sensitive and selective spectrophotometric method is suggested for the determination of traces of iron(III) based on complex formation with hematoxylin in presence of cetyltrimethylammonium bromide (CTAB). Addition of CTAB shifted the absorption maximum of the iron-hematoxylin complex from 630 to 640 nm and increased its molar absorptivity from 9.88 × 10⁴ to 1.16 × 10⁵ 1·mol^–1·cm^–1. The method adhered to Beer's law up to 0.4 and 0.2 g/ml of iron in presence and absence of CTAB, respectively. The corresponding values of Sandell's sensitivity were 0.5 and 0.6 ng·cm^–2. The effect of reagent and surfactant concentrations, pH and standing time were investigated. EDTA, tartrate and sodium fluoride were used as masking agents for most of the interfering ions. The method was successfully used for the determination of iron in aluminium metal and some non-ferrous alloys.     

Untersuchungen über das morpholin-N-dithiocarbonsaure Morpholinium (MDCM) als Reagens in der quantitativen Analytik. XI

Zusammenfassung Eine neue spektralphotometrische Methode zur Bestimmung kleiner Tantalmengen wird vorgeschlagen, die auf der Bildung einer stabilen, extrahierbaren Komplexverbindung beruht, wobei morpholindithiocarbonsaures Morpholinium als Reagens dient. Der Einfluß von Fremdionen wurde untersucht und das Verfahren statistisch geprüft. Die Absorptionsmessungen erfolgen bei 288 nm. Der molare Extinktionskoeffizient beträgt 60440 1 · Mol^–1 · cm^–1. Das Lambert-Beersche Gesetz ist im Bereich von 0,3–3g Ta/ml erfüllt.

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Studies on the morpholine-N-dithiocarboxylic acid morpholinium (MDCM) as a reagent in quantitative analysis. XI

Summary A new spectrophotometric method for the determination of small amounts of tantalum is proposed which is based on the formation of a stable, extractable complex using morpholine-N-dithiocarboxylic acid morpholinium as the reagent. The effect of diverse ions was investigated and the method tested statistically. The absorbance is to be measured at 288 nm with corresponding molar absorptivity of 604401 · mole^–1 · cm^–1. Conformity to Beer's law was observed for 0.3 to 3 ppm of tantalum.

     

Reactions of molybdate ions with polyphenol reagents: Determination of molybdenum with Pyrocatechol Violet and Alizarin Red S

Summary Molybdate forms a 11 complex with Pyrocatechol Violet in weakly acidic solutions. At the optimum pH 2.7 the apparent stability constant is (1.52±0.12)×10⁴l·mole^–1 and the molar absorptivity 2.70×10⁴l·mole^–1·cm^–1 at 540 nm. At higher and lower pH the stability of the complex decreases. In the pH range 2–5 molybdate forms a 12 complex with Alizarin Red S. The apparent stability constant is (4.8±0.6)×10⁷l·mole^–1 at the optimum pH 3.8 and the molar absorptivity (9.30±0.30)×10³l· mole^–1·cm^–1 at 480 nm. In 0.1M acid solution a less stablel: 1 complex exists, logK=4.2. Both dyes are appropriate reagents for estimation of molybdate when present in weakly or strongly acidic solutions. Near to the isoelectric point of molybdic acid (pH 1.5–2.0) accurate analysis data can be obtained only when the molybdate solution to be analysed is neutralized and boiled for 10 min to transform the less reactive polymeric molybdenum species. It is thought that hexacoordinated Mo(OH)₆ is the reactive species, forming esters with the polyphenols used.

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Reaktionen von Molybdat mit Polypbenol-Reagenzien: Bestimmung von Molybdän mit Brenzcatechinviolett und Alizarinrot S

Zusammenfassung Molybdat bildet mit Brenzcatechinviolett in schwach saurer Lösung einen 11-Komplex. Bei dem optimalen pH 2,7 beträgt die scheinbare Stabilitätskonstante (1,52 ±0,12)×10⁴l·mol^–1 und die molare Extinktion bei 540 nm 2,70×10⁴l·mol^–1·cm^–1. Bei höherem oder niedrigerem pH nimmt die Stabilität des Komplexes ab. Im pH-Gebiet 2–5 bildet Molybdat mit Alizarinrot S einen 12-Komplex. Dessen scheinbare Stabilitätskonstante beträgt (4,8±0,6)× 10⁷l·mol^–1 bei dem optimalen pH=3,8 und die molare Extinktion (9,30± 0,30)×10³l·mol^–1·cm^–1 bei 480 nm. In 0,1M saurer Lösung existiert ein weniger stabiler 11-Komplex, dessen logK=4,2. Beide Farbstoffe eignen sich für die Bestimmung von Molybdat in schwach oder stark saurer Lösung. In der Nähe des isoelektrischen Punktes der Molybdänsäure (pH 1,5-2,0) können genaue Analysenergebnisse nur erhalten werden, wenn die Molybdatlösung vorher neutralisiert und 10 min gekocht wird, um die weniger reaktionsfähigen polymeren Formen des Molybdäns abzubauen. Es wird angenommen, daß Mo(OH)₆ die hexakoordinierte reaktionsfähige Form darstellt, die mit den Polyphenolen Ester bildet.

     

Spectrophotometric determination of microgram amounts of chromium(VI) and total chromium in waste water

Summary A spectrophotometric method has been developed for the determination of chromium in waste water with 5-Br-PADAP (2-(5-brorno-2-pyridylazo)-5-diethylaminophenol). Chromium(III) forms a blue-purple complex at pH 4.7 upon heating. The color is very stable and is highly sensitive for chromium. At 600 nm it obeys Beer's law in the concentration range of 0–15g of Cr(III) per 25 ml. The sensitivity and molar absorptivity of the reaction are 0.00065g of Cr(III) per cm² and 7.93×10⁴1 · mole^–1 · cm^–1, respectively. The continuous variation and molar ratio methods indicate that chromium forms 12 complex with the ligand.

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Spektrophotometrische Bestimmung von Mikrogramm-Mengen Chrom(VI) und Gesamt-Mengen Chrom in Abwasser

Zusammenfassung Eine spectrophotometrische Methode zur Bestimmung von Chrom in Abwasser mit 5-Br-PADAP wurde ausgearbeitet. Chrom(III) bildet mit 5-Br-PADAP bei pH 4,7 durch Erhitzen einen blaupurpurnen Komplex. Die Farbe ist sehr beständig. Bei 600 nm entspricht die Färbung dem Beerschen Gesetz zwischen 0 und 15g Cr(III)/25 ml. Die Empfindlichkeit der Reaktion beträgt 0,00065g Cr(III)/cm² und die molare Absorption 7.93×10⁴ 1 · mol^–1 · cm^–1. Die Untersuchung nach Job ergab für den Komplex das Molverhältnis Cr:Reagens=12.

     

Spectrophotometric determination of iron in alloys and ores with 1-(2-pyridylmethylideneamine)-5-(salicylideneamine)thiourea

Summary A spectrophotometric method for the determination of iron is described. The green Fe(II) complex is formed at pH 4.8 in a medium containing 40% dimethylformamide and 0.8 g/l ascorbic acid, and the absorbance is measured at 635 nm. The molar absorptivity is 5.7×10³lo·mole^–1·cm^–1. The method has been applied with good results to the determination of iron in six alloys and ores.

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Spektrophotometrische Bestimmung von Eisen in Legierungen und Erzen mit 1-(2-Pyridylmethylidenamin)-5-(salicylidenamin)-thioharnstoff

Zusammenfassung Ein spektrophotometrisches Verfahren zur Eisenbestimmung wurde beschrieben. Der grüne Fe(II)-Komplex bildet sich bei pH 4,8 in einem Medium aus 40% Dimethylformamid und 0,8 g/l Askorbinsäure. Die Absorbanz wird bei 635 nm gemessen. Die molare Absorptivität beträgt 5,7× 10³l·mol^–1·cm^–1. Die Methode gab gute Resultate bei der Bestimmung von Eisen in sechs Legierungen und Erzen.

     

3-Hydroxy-2-(2"-Thienyl)-4H-Chromon-4-one as a Spectrophotometric Reagent for the Trace Determination of Zirconium in an Aqueous Phase

A rapid, simple, selective, and sensitive method for the trace determination of zirconium has been developed based on the reaction of 3-hydroxy-2-(2"-thienyl)-4H-chromon-4-one in an hydrochloric acid medium to form a yellow–colored complex which is rendered water soluble by the micellar action of Triton X-100 and measured at 415 nm. Most of the metal ions do not interfere with the determination. Beer's law is obeyed in the concentration range 0–2.0 g/mL and the molar absorptivity of the complex is 2.73 × 10⁴L mol^–1cm^–1; Sandell's sensitivity is found to be 0.0034 g cm^–2. The method has been applied for the determination of zirconium in various samples, and satisfactory results have been obtained.     

Diphenylcarbazone as a sensitive reagent for the spectrophotometric determination of iridium(IV)

Summary The blue iridium(IV)-diphenylcarbazone complex, formed by heating the solutions in boiling water bath for 45 minutes, having an absorption maximum at 550 nm with maximum molar absorptivity of 1.90·10⁴l·cm^–1·mole^–1 (within 1.5 %) is recommended for the spectrophotometric determination of 40–240g iridium(IV) in 25–60 % ethanol medium. The complex formed in solutions at pH 3.5–7.0, after formation, is stable within the pH range 2.5 to 9.2. The effect of foreign ions has been investigated.

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Zusammenfassung Der blaue Iridium(IV)-diphenylcarbazon-Komplex entsteht beim Erwärmen der beiden Lösungen im siedenden Wasserbad für 45 Min. Er hat ein Absorptionsmaximum bei 550 nm und eine molare Extinktion von 1,90 × 10⁴ l·cm^–1·mole^–1. Diese Farbreaktion wird zur spektrophotometrischen Bestimmung von 40–240g Ir(IV) in 25-bis 60%igem Äthanol empfohlen. Der bei pH 3,5–7,0 entstandene Komplex ist zwischen pH 2,5 und 9,2 beständig. Der Einfluß von Fremdionen wurde untersucht.