Solid phase extraction of zirconium as arsenazo(III) complex on agar and spectrophotometric determination

A new solid phase extraction method for the separation and determination of zirconium using agar as an adsorbent is described. The method is based on the adsorption of zirconium as arsenazo(III) complex on agar in a mini-column, elution with sulfuric acid-acetone mixture and determination by spectrophotometry. The effect of different parameters such as pH, concentration of the reagent, eluting reagent, and volume of the sample, amount of the adsorbent and interfering ions was investigated. The calibration graph was linear in the range of 5?C300 ng ml^?1 of zirconium under optimum conditions. The limit of detection based on 3S_b was 1.3 ng ml^?1 and the relative standard deviation (R.S.D) for ten replicate measurements of 15 and 200 ng ml^?1 of zirconium was 3.7 and 1.8%, respectively. The method was applied to the determination of zirconium in water and soil samples.     

Extraction of palladium from nitric acid medium and its spectrophotometric determination using arsenazo III

Summary Di-octyl sulphoxide in xylene was successfully employed for extracting palladium from 0.5 to 1.5 mol/l nitric acid medium. The extracted species was found to be Pd(NO₃)₂·2DOSO. The palladium was back extracted into a mixture of 2 mol/l sodium carbonate and 0.05 mol/l ammonia. The recovery was found to be quantitative. A spectrophotometric method using Arsenazo III was developed in nitric acid medium for the determination of palladium. The colour development was found to be maximum in the acid range of 2.5 to 5 mol/l. Beer's law was found to be obeyed in 1 to 100 g range of palladium. The molar extinction coefficient was found to be 2.26×10⁴ l/mol/cm. The RSD obtained at 16 g of palladium was 5%.     

Flow injection spectrophotometric determination of N-acetyl-L-cysteine as a complex with palladium(II)

We describe a new method using flow-injection analysis with spectro-photometric detection, suitable for the determination of N-acetyl-L-cysteine (NAC). The proposed method is appropriate for the determination of NAC in reaction with Pd(2+) ions in the concentration range from 1.0 × 10(-5) mol L(-1) to 6.0 × 10(-5) mol L(-1). The detection limit NAC was 5.84 × 10(-6) mol L(-1) and the recorded relative standard deviation of the method is in the range from 1.67 to 4.11%. NAC and Pd(2+) form complexes of Pd(2+):NAC molar ratios of 1:1 and 1:2, depending on the ratio of their analytical concentrations. The cumulative conditional stability constant for the Pd(NAC)(2)(2+) complex is β(12)' = 2.69 × 10(9) L(2) mol(-2). The proposed method was compared with the classic spectrophotometric determination of NAC, using the same reagent, PdCl(2), and had shown certain advantages: a) shorter analysis time; b) the use of smaller volumes of sample and reagents, which make the proposed method cheaper and faster for NAC determination in real samples without sample pretreatment.     

Liquid-liquid extraction and spectrophotometric determination of palladium(II) and ruthenium (III) with isonitrosoethylbenzoylacetate

Summary A method is described for the extractive spectrophotometric determination of palladium or ruthenium (III) using isonitrosoethylbenzoylacetate as the reagent. The yellow Pd-INEBA complex extracted into chloroform absorbs at 410 nm and conforms to Beer's law in the range of 10–110g of Pd per 10 ml of organic phase. The purple Ru-INEBA complex extracted into MIBK absorbs at 500 nm and conforms to Beer's law in the range of 25–125g of Ru per 10 ml of organic phase. The method affords the determination of both Pd and Ru in the presence of large number of cations and anions.

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Flüssig-flüssig-Extraktion und spektrophotometriscbe Bestimmung von Palladium(II) und Ruthenium(III) mit Isonitrosoäthylbenzoylacetat (IÄBA)

Zusammenfassung Eine Methode für die Extraktion und spektrophotometrische Bestimmung von Pd oder Ru mit IÄBA wurde beschrieben. Der gelbe Pd-Komplex absorbiert in chloroformischer Lösung bei 410 nm und entspricht dem Beerschen Gesetz für 10–110g Pd/10 ml organische Phase. Der rote Ru-Komplex absorbiert in MIBK bei 500 nm und entspricht dem Beerschen Gesetz für 25–125g Ru/10 ml. Das Verfahren eignet sich für die Bestimmung der beiden Metalle in Gegenwart zahlreicher Kationen und Anionen.

     

A spectrophotometric investigation into the complex formation between bismuth(III) and 2-mercaptoethanol in aqueous solution

Complex formation between bismuth(III) and 2-mercaptoethanol was studied at 25°C and I = 1.0 mol dm^?3 HClO₄. The results were used to test the validity of an empirical equation for the calculation of formation constants.     

Separation and spectrophotometric determination of uranium (VI) by extraction with arsenazo III and zephiramine

Summary Microgram quantities of uranium(VI) can be determined at 655 nm after separation by chloroform extraction of its Arsenazo III complex with Zephiramine. The extracted uranium can be back-extracted with an aqueous solution of ammonium carbonate. Uranium can be separated from aluminium, iron(II), and some other elements. Probably the same species, i. e., the ion association compound between the uranium (VI)-Arsenazo III complex and Zephiramine are involved during the extraction and the froth flotation.

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Zusammenfassung Mikrogrammengen Uran(VI) lassen sich nach Chloroformextraktion seines Arsenazo-III-Komplexes mit Zephiramin bei 655 nm messen. Das extrahierte Uran kann man mit wäßriger Ammoniumcarbonatlösung rück-extrahieren. Von Aluminium, Eisen(II) und einigen anderen Elementen kann es so getrennt werden. Wahrscheinlich handelt es sich bei der Extraktion und der Schaumflotation um die gleiche Ionenassoziatverbindung des Uran (VI)-Arsenazo-III-Komplexes mit Zephiramin.

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Presented at the 24th Annual Meeting of the Japan Society for Analytical Chemistry, Sapporo, October, 1975.     

Copper(II)-cetyltrimethylammonium chloride-chromal blue G ternary complex and its application to the spectrophotometric determination of copper(II)

A sensitive spectrophotometric method for the determination of copper(II) based on a ternary complex with chromal blue G, a triphenylmethane reagent in the presence of cetyltrimethylammonium chloride, is described. The sensitivity of color reaction between copper and chromal blue G has been greatly increased by the sensitizing action of cetyltrimethylammonium chloride, a cationic surfactant. The color development of the ternary complex can be utilized in the highly sensitive spectrophotometric determination of copper. The molar absorptivity of the binary complex between copper and chromal blue G ε_630nm = 9.56 × 10³liters · mol⁻¹ · cm⁻¹ is enchanced on ternary complex formation to ε_{542 nm} = 4.78 × 10⁴liters · mol⁻¹ · cm⁻¹. The ternary complex gave a maximal absorbance at 542 nm in the pH range 9.8–11. Beer's law is obeyed up to at least 1.2 ppm of copper. The maximal absorbance of the ternary complex was found to develop within 5 min and then it remains constant for several hours. The formation constant of the ternary complex is calculated to be 8.6 × 10¹⁰ under these conditions.     

Analytical determination of dimethyl sulphoxide by complex formation with the pentacyanoferrate(II) ion

A method for determination of small amounts of dimethyl sulphoxide and non-hindered sulphoxides is proposed, based on selective reaction with the aquapentacyanoferrate(II) ion, leading to stable complexes which can be detected electrochemically.     

Extractive spectrophotometric determination of palladium(II) and platinum(II) with 2-allylthiourea and thiocyanate in the presence of EDTA

Palladium(II) and platinum(II) react with 2-allylthiourea and thiocyanate to form colored complexes stable in the presence of EDTA and extractable into isoamyl alcohol. Based on these properties a method was worked out for the extractive spectrophotometric determination of palladium(II) and platinum(II) in the presence of several cations.     

Asynchronous merging zones system: spectrophotometric determination of Fe(II) and Fe(III) in pharmaceutical products

An asynchronous merging zones was proposed with simultaneous introduction of the sample and of the modifier reagent, ascorbic acid in the studied case, for sequential determination of Fe(II) and Fe(III) in pharmaceutical products. The sample and reagent attained a merging point at different times owing to the use of a delay reactor in the reagent channel. By inserting a large sample and controlling the dispersion in the flow system, Fe(II) and Fe(III) were sequentially measured in the front and in the rear of the sample zone, respectively. The results obtained for Fe redox speciation in pharmaceutical products are in agreement at a 95% confidence level with those obtained with a manual spectrophotometric procedure. The analytical frequency with the proposed flow analysis system was 54 samples h(-1), i.e. 108 determinations h(-1).     

A rapid method for the spectrophotometric determination of palladium(II) and osmium(VIII)

Propionyl promazine phosphate is proposed as a new reagent for the rapid spectrophotometric determination of microgram amounts of Pd(II) and Os(VII). PPP instantaneously forms an orange-red 1:1 complex with Pd(II) in sodium acetate-hydrochloric acid buffer of pH 0.8 to 4.0 at room temperature. The reagent also forms an orange-red radical cation with Os(VIII) in 0.5 to 2.0 M hydrochloric acid. The Pd-PPP complex exhibits an absorption maximum at 490–500 nm with molar absorptivity of 7.1 × 10³ liter mol^?1 cm^?1. The Os-PPP radical cation has an absorption maximum at 505–515 nm with molar absorptivity of 2.21 × 10⁴ liters mol^?1 cm^?1. The Sandell sensitivity is 0.022 μg/cm² (Pd) and 0.008 μg/ cm² (Os). Beer's law is valid over the concentration range 0.2 to 21 ppm (Pd) and 0.2 to 4.2 ppm (Os). The proposed method offers the advantages of simplicity, rapidity, and without the need for heating or extraction. The reagent is used for the determination of Pd in the synthetic mixtures corresponding to Pd alloys used in jewelery and Os in osmiridium alloy.     

A spectrophotometric study of the formation of the peroxotitanium(IV) complex and its application to the determination of beryllium

The formation of peroxotitanium(IV) complexes has been studied spectrophotometrically in (a)Ti(IV)-H₂O₂,(b)Ti(IV)-H₂O₂-HF and (c)Ti(IV)-H₂O₂-HF-Be(II) systems containing 2M hydrochloric acid. In system (a),only a 1:1 peroxotitanium(IV) complex is evident. In system (b), the competitive formation of the peroxotitanium(IV) complex and fluorotitanium(IV) complexes is discussed. In system (c), the formation of fluoroberyllium(II) complexes causes an increase in concentration of the peroxotitanium(IV) complex which is proportional to the concentration of added beryllium(II). The determination of beryllium in a Cu-Be alloy was successful with a Ti(IV)-H₂O₂-HF reagent.     

The spectrophotometric determination of thallium(iii)by ternary complex formation

If thallium(III) is added to an aqueous solution of potassium thiocyanate containing a large amount of pyridine in the pH range 5.2–5.5, a yellow solution which is stable in diffuse light is obtained. The yellow colour can be measured at 405 nm for the colorimetric determination of thallium(III) in the range 20–300 μg Tl ml^-1. The complex is a mixed ligand complex with a metal-ligand ratio of 1:2:2. Thallium(I) does not interfere. The interference of various other metal ions and anions is discussed.     

Analytical application and spectrophotometric study of the scandium-indoferron complex

A new spectrophotometric method for microgram amounts of scandium with indoferron is described. The molar absorptivity is 960 l.mole⁻¹.mm⁻¹ at 600 nm. Uranium and the rare earths do not interfere, if present in amounts less than 50 μg. Scandium in silicate rocks can be determined by the procedure after separation of the scandium by a three-stage ion-exchange Chromatographic technique. The acid dissociation constants of indoferron and conditional formation constants of the 1:2 complex have been determined spectrophotometrically.     

二溴羧基偶氮胂催化动力学光度法测定痕量锡

基于稀H2SO4介质中,痕量锡（Ⅳ）催化KBrO3氧化二溴羧基偶氮胂（DBCAA）的褪色反应,建立了测定痕量锡（Ⅳ）的催化动力学光度法。方法检出限为0．23μg／L,线性范围为0．0～8．0μg／L。结合巯基葡聚糖凝胶（SDG）分离富集,可用于测定环境水样、人发及岩石样品中的痕量锡（Ⅳ）。     

偶氮胂I-高碘酸钾催化光度法测定痕量Mn(Ⅱ)

研究了在HAc—NH4Ac介质中，以1，10-菲啰啉为活化剂，锰(Ⅱ)催化高碘酸钾氧化偶氮胂I褪色反应的条件及影响因素，建立了动力学光度法测定痕量Mn(Ⅱ)的新方法。方法线性范围为0-80μg/L，检出限为6．3ng/mL，对60μg/L,Mn(Ⅱ)测定的相对标准偏差为2．6％。导出了动力学方程，该催化反应的表观活化能为130．4kJ／mol。已用于野菜、水果样品中锰(Ⅱ)的测定。     

Rapid spectrophotometric determination of chromium(III)

A spectrophotometric procedure is suggested for the determination of Cr(III). The reaction between Cr(III) and 2-(5-bromo-2-pyridylazo)-5-dimethylaminophenol is accelerated by sodium dodecyl sulphate(SDS), sodium benzoate causes a further increase in the absorbance of the chelate. The optimum pH range for the reaction is 5-5.8(benzoate buffer). The chelate exhibits maximum absorbance at 590 nm, obeys Beer's law over the concentration range 0.02-0.56 microg/ml of Cr(III), has molar absorptivity of 7.8 x 10(4) 1. mol(-1) cm(-1) and a Sandell sensitivity of 0.66 ng/cm. The metal to ligand ratio is 1:2 in the absence of SDS and 1:1 in its presence. A procedure for the determination of Cr(III) and Cr(VI), when present together, is described. The method has been applied to the analysis of Cr(III) in tap water.