Spectrophotometric Determination of Iron (III) Using 3-Hydroxy-2-Methyl-1,4-Naphthoquinone Monoxime (HMNQM)

Iron (III) forms brown coloured complex with 3-hydroxy-2-methyl-1,4-naphthoquinone monoxime. The iron (III)-HMNQM complex is found to be soluble in DMF and exhibits maximum absorption at 470 nm in the pH range 4.5–5.5. Beer's law is obeyed upto 5.58 ppm of iron (III) and sensitivity of the reaction is 0.0046 μg/cm², with molar absorptivity of 1.21×10⁴ ? mole^?1 cm^?1. The method has been used for the determination of iron (III) in alloys.     

Spectrophotometry Determination of Cobalt after Extraction of its Ternary Complex with 3-(4-Phenyl-2-Pyridyl)-5,6-Diphenyl-1,2,4-Triazine and Tetraphenylborate into Molten Naphthalene

The reaction of 3-(4-phenyl-2-pyridyl)-5,6-diphenyl-1,2,4-triazine (PPDT) and tetraphenylborate (TPB) with cobalt (II) has been studied to determine the optimum conditions for the extraction and quantitative spectrophotometry determination of this metal. The ternary complex is extracted into molten naphthalene at pH 3.6–7.4. The solid naphthalene containing the cobalt associated complex is separated by filtration and dissolved in acetonitrile. Beer's law is obeyed in the concentration range 8–140 μg cobalt in 10 ml of acetonitrile solution. The molar absorptivity and sensitivity are 4.2×10³ l·mol^?1·cm^?1 and 0.01408 μg/cm², respectively. The other factors such as pH, amounts of reagents and naphthalene, shaking and standing times, and the effect of diverse ions are studied. The method has been applied to the determination of cobalt in iron steel alloys.     

2-Methyl-1, 4-Naphthoquinone Thiosemicarbazone as a Sensitive and Selective Chromogenic Reagent for Microdetermination of Palladium (II)

A simple, sensitive and selective procedure has been developed for the spectrophotometric determination of palladium. Palladium (II) reacts with 2-methyl-1,4-naphthoquinone thiosemicarbazone to form an orange brown complex in the pH range 8.2–9.5. The sensitivity, in terms of Sandell's definition, is 0.0025 μg Pd/cm² at 500 nm. The system adheres to Beer's law upto 2.66 ppm of palladium and optimum concentration range for the determination of the metal is 0.3–2.29 ppm with molar absorbtivity of 4.2×10⁴ ? mole^?1 cm^?1. The complex has 1:1 molar composition, as deduced by Job's method. The determination of palladium has been carried out in presence of foreign ions especially in presence of eighth group metals.     

Rapid spectrophotometric determination of iron in natural waters with 4-(2-thiazolylazo)-6-chlororesorcinol

4-(2-Thiazolylazo)-6-chlororesorcinol reacts sensitively with iron(II) to form a water-soluble brown complex which has a characteristic absorption at 741 nm. By utilizing this absorption, rapid and selective spectrophotometric determination of iron has been developed. The absorbance is constant at pH 8.7 to 10.9 and Beer's law holds up to 1.8 ppm of iron, with a molar absorptivity of 3.13 × 10⁴ liters mol^?1 cm^?1. Many types of ions are tolerable and the method has been applied successfully to the determination of iron in river waters.     

Spectrophotometric Determination of Diphenadione Via its Metal Complexes

Abstract

Spectrophotometric procedure is described for the quantitative determination of diphenadione [2-(diphenylacetyl)-1,3-indandione], based on direct spectrophotometric measurements of the absorbances of its iron (III), iron (II) and cobalt (II), metal complexes at 488 nm, 505 nm and (334 nm, 372 nm), respectively. The drug reacts with metals in the ratio of 3:1 and 2:1 for iron (III) and for both iron (II) and cobalt (II) respectively. The obtained complexes have apparent molar absorptivities of 1.48 × 10³ 1 mol^?1 cm^?1, 0.714 × 10³ 1 mol^?1cm^?1 and (1.70 × 10³ 1 mol^?1cm^?1, 1.93 × 10³ 1 mol^?1cm^?1) for iron (III), iron (II) and cobalt (II) complexes, respectively. The procedure is suggested for the determination of 51–400 μg.ml^?1 diphenadione via the iron (II) complex and 35–170 μg.ml^?1 diphenadione via both cobalt (II) and iron (III) complexes. The suggested procedure has accuracies of 99.79 ± 0.67%, 99.64 ± 0.37% and (100.09 ± 0.53%, 99.99 ± 0.42%) for the metal complexes of iron (III), iron (II) and cobalt (II), respectively.     

Selective Spectrophotometric Determination of Copper in Milk with Phenanthraquinone Monothiosemicarbazone

The red complex formed by copper (II) and phenanthraquinone monothiosemicarbazone has an absorption maximum at 530 nm with a molar absorptivity of 14000 cm^?1 mole^?1. The pH range for the determination is 1.1–6.6. Optimum range of concentration for accurate determination is 0.50–3.47 ppm of copper (II) in 50% methanol medium. The limits of interference due to foreign ions have been studied. The method has been successfully employed for the determination of copper in various samples of milk.     

Spectrophotometric Determination of Vanadium in Complex Materials Using N-m-TMBHA and Thiocyanate

Abstract

Vanadium(V) reacts with N-m-Tolyl-p-methoxy benzohydroxamic acid to form 1:2 (metal to ligand) complex containing a basic V=O group and an acidic V-OH group, which forms addition compounds with thiocyanate to give a hyper and bathochromic effect in chloroform. On the basis of this bathochromic effect of thiocyanate a rapid, selective and sensitive method for the spectrophotometric determination of vanadium(V) has been developed. The blue coloured complex of vanadium(V) is extractable in chloroform having absorption maxima at 580nm and max 7100 ±50 1. mole^?1 cm^?1. The method is free from interferences of Mo(VI), W(VI), Zr(IV) and has been successfully applied for the analysis of steels and other complex materials.     

Spectrophotometric Determination of Cobalt,Nickel and Palladium after Extraction with Thioxanthate into Molten Naphthalene

Cobalt, nickel and palladium have been extracted with thioxanthate into molten naphthalene (85–90°C). Various parameters involved in the extraction have been studied and composition of the extracted complex established in each case. Cobalt. nickel and palladium thioxanthates are extracted in the pH range, Co: 5.0–9.5. Ni: 3.9–7.4 and Pd: 2.0–9.5 and can be determined spectrophotometrically at 390. 500 and 345 nm respectively. The molar absorptivities are calculated to be Co: 6.187×10³ ? mol^?1 cm^?1, Ni: 8.8×10³ ? mol^?1 cm^?1 and Pd: 1.16×10⁴ ? mol^?1 cm^?1 with sensitivities in terms of Sandell's defication are; 0.0095 μg Co/cm² at 390 nm, 0.0060 μg Ni/cm² at 500 nm and 0.0091 μg Pd/cm² at 345 nm respectively. These conditions have been utilized for the determination of these metals in alloys and also for the simultaneous determination of cobalt and nickel in an alloy.     

Spectroscopic study of 2,3-Bis(p-methoxybenzoyl)cyclopentadiene as potential iron(III)-chelating agent

2,3-Bis(p-methoxybenzoyl)cyclopentadiene was studied as iron(III)-chelating agent. Its pK _a value was determined by spectrophotometry (pK _a = 8.27 ± 0.02 at 25 ± 0.1°C; λ = 421 nm). 2,3-Bis(p-methoxybenzoyl)cyclopentadiene reacts with Fe³⁺ ions in aqueous ethanol (1:1, by volume) to give a 2:1 ligandmetal complex. The effects of different factors on the complex formation were studied. The reaction of 2,3-bis(p-methoxybenzoyl)cyclopentadiene with Fe³⁺ ions can be used as an alternative method for spectrophotometric determination of iron(III) in a range of concentrations from 0.1 to 1 μg cm⁻³, where the Beer law is fulfilled with a correlation coefficient of 0.9992. The results of spectrophotometric determination of iron(III) in geological materials (iron rock) showed very good agreement with those obtained by the atomic absorption measurements. Published in Russian in Zhurnal Obshchei Khimii, 2006, Vol. 76, No. 5, pp. 790–793. The text was submitted by the authors in English.     

Spectrophotometric Determination of Albendazole Drug in Tablets: Spectroscopic Characterization of the Charge-transfer Solid Complexes

Simple, rapid and reliable method for the determination of albendazole (ABZ) was described. This includes the utility of some Π‐acceptors such as 2,3‐dichloro‐5,6‐dicyano‐p‐benzoquinone (DDQ) and 3,6‐dichloro‐2,5‐dihy‐ droxy‐p‐benzoquinone (p‐CLA) for estimation of ABZ drug (act as donor). The experimental conditions were optimized and the system obeys Beer's law for 7.50–80 and 10.00–85.00 µg·mL^?1 of ABZ using DDQ and p‐CLA, respectively. The molar absorptivity and Sandell sensitivity were calculated to be 1.83×10³ and 1.12×10³ L·mol^?1·cm^?1, and 2.60 and 3.40 ng·cm^?2 using DDQ and p‐CLA, respectively. The limits of detection and quantification were calculated to be (7.42 and 6.73) and (9.94 and 4.13) µg·mL^?1 using DDQ and p‐CLA, respectively. The proposed methods were successfully applied to the determination of ABZ in commercially available dosage forms. The reliability of the assays was established by parallel determination by the official method and recovery studies. The chemical structures of the solid charge‐transfer (CT) complexes formed via reaction between ABZ under study and Π‐acceptors, have been elucidated using elemental analyses (C, H and N), IR, ¹H NMR and mass spectra.     

Spectrophotometric Determination of Iron In Wines,Vegetables, Pharmaceutical Compounds and Minerals With Mandelohydroxamic Acid (Mha)

Abstract

A new reagent, mandelohydroxamic acid (MHA), which has an easy synthesis and an high water solubility (64.48 gL^?1) is proposed for a simple, rapid, selective and sensitive method for the spectrophotometric determination of iron based upon the formation of the MHA-Fe(III) complex and its extraction into n-butanol under optimum operating conditions. A yellow color is formed when the complex is extracted from acidic aqueous medium (Vw/Vo[dbnd]5) in the organic solvent (apparent molar absortivity 1.15 10⁴ L mol^?1 cm^?1 at a wavenlength of 430 nm). the relative error is 0.5% (2 ppm of iron) and the detection limit is 0.05 g mL^?1 of Fe(III). the method has been applied to the determination of iron in wines, vegetables, pharmaceutical compounds and minerals.     

Spectrophotometric Determination of Cobalt in Vitamin Preparations,Steel and Iron Using 2-Hydroxy- 1-Naphthaldehyde Guanylhydrazone

Abstract

A new spectrophotometric determination of cobalt with 2-hydroxy-1-naphthaldehyde guanylhydrazone in acid medium is described. The method is developed on the basis of a yellow cobalt (III) complex (molar absorptivity 1.32×10^?4 L.mol^?1.cm^?1 at 416 nm, stoichiometry 2:1). The method was applied to the determination of cobalt in vitamin preparations, steel and high-purity iron.     

Extractive-spectrophotometric determination of traces of copper(II) with 4-(p-nitrophenylazo)-2-amino-3-pyridinol

A new extractive-spectrophotometric method for determination of copper(II) with 4-(p-nitrophenylazo)-2-amino-3-pyridinol is proposed. The established stoichiometry and extraction constant are 2:1 ligand:metal and ?1.55, respectively. The molar absorptivity of the complex is 5.19 × 10⁴ liters mol^?1 cm^?1 at 560 nm and Sandell's sensitivity is 1.2 ng cm^?2. The best conditions for determination and effect of other ions are studied. The method proposed is applied in the determination of copper in whisky, liver of fish, and seawater.     

Spectrophotometric Determination of Copper with Diacetylmonoquinolylhydrazone

Synthesis of a new reagent diacetylmonoquinolylhydrazone (DAmQH) and its application in the selective spectrophotometric determination of copper is presented. DAmQH reacts with copper instantaneously to form a green complex in the pH range 7.5–11.6 with molar absorptivity 1.45 × 10⁴ l mole^?1 cm^?1. Beer's law is obeyed upto 2.20 ppm of copper. Copper has also been analysed in several alloys.     

Spectrophotometric study on the reactions of iron(II) with bromopyrogallol red and pyrogallol red in the presence of quaternary ammonium salt

Iron(II) in the presence of quaternary ammonium salt reacts with bromopyrogallol red (BPR) and pyrogallol red (PR) to form a ternary complex. The ternary complex Fe(II)-BPR-TDTA is suitable for the determination of trace amounts of iron. The complex has an absorbance maximum at 635 nm with molar absorptivity 5.6 × 10⁴ liters mol^?1 cm^?1, in which the molar ratio of iron(II) to BPR is 1:3. Beer's law is obeyed over the range 0.08–0.5 μg/ml of iron. Masking agents allow most interferences to be suppressed.     

Analytical study of the phenyl-2-pyridyl ketone azine-palladium system. Photometric determination of palladium

Phenyl-2-pyridyl ketone azine reacts with palladium(II) to produce a yellow 1:1 complex (λ_max = 425 nm, ? = 10.4 × 10³M^?1 cm^?1 in aqueous ethanolic solution) and a red-violet 3:1 complex (λ_max = 530?540 and 380?390 nm). The yellow complex in aqueous ethanolic solution has been used for the spectrophotometric determination of trace amounts of palladium. The method has been applied to the determination of palladium in some catalysts and one mineral.     

Spectrophotometric Determination of Trace Amounts of Titanium in Geochemical and Metallurgical Samples

Abstract

The reaction between cyclohexan-1,2-dione bissalicyloylhydrazone and titanium(IV) has been studied spectrophotometrically. An orange complex (λ = 470 nm, ? = 1.49 × 10⁴ 1.mol^?1.cm^?1) is quickly formed at pH 1–2.5 in a 3+2 V/V ethanol/water medium. Interferences (more than 65 species) have been investigated. In presence of some masking agents most of metal ions do not interfere. The orange complex has been satisfactorily used for the determination of titanium in amphibolites, granites, suspended matter, Portland cement, bauxite, cast iron and duraluminium alloy. The results are compared with those obtained using AAS and ICP methods.     

Spectrophotometric studies on complexation reactions of some water-soluble 5-nitro-2-pyridylhydrazones with cobalt. Spectrophotometric and derivative spectrophotometric determination of trace cobalt with 2-benzimidazolyl-3-sulphophenylmethanone 5-nitro-2-pyridylhydrazone

The complexation reactions of four water-soluble hydrazones, 2-quinolyl-3-sulphophenylmethanone 5-nitro-2-pyridylhydrazone, 3-sulphophenyl-2-thiazolylmethanone 5-nitro-2-pyridylhydrazone (STNPH), 2-benzothiazolyl-3-sulphophenylmethanone 5-nitro-2-pyridylhydrazone and 2-benzimidazolyl-3-sulphophenylmethanone 5-nitro-2-pyridylhydrazone (BISNPH), with cobalt(II) were studied spectrophotometrically. These hydrazones react with cobalt(II) to form stable 1:2 (metal:ligand) complexes, except for STNPH, which forms a 1:1 complex, with high molar absorptivities. A sensitive and selective spectrophotometric method for the determination of cobalt with BISNPH has been developed. The cobalt(II)-BISNPH complex is formed quantitatively in the pH range 2.7–9.4 and oxidized rapidly to give the corresponding cobalt(III) complex with an absorption maximum at 517 nm. Beer's law is obeyed over the range 0.02–1.0 μg ml^?1 and the apparent molar absorptivity of the cobalt(III) complex is 6.65 × 10⁴ l mol^?1 cm^?1 at 517 nm. The method was applied to the determination of cobalt in iron and steel samples with satisfactory results. The sensitivity is increased 11-fold by use of second-derivative spectrophotometry.     

The structure and magnetic properties of μ3-oxotriiron(III) complex [Fe3O(OBz)6(CH3OH)3](NO3)(CH3OH)2

A new μ₃-O triiron(III) complex [Fe₃O(OBz)₆(CH₃OH)₃](NO₃)(CH₃OH)₂ (HOBZ = benzoic acid) has been synthesized, its structure has been determined and variable temperature magnetic susceptility has also been measured. In the molecule, three iron atoms formed an equilateral triangle with μ₃-O in center. The fitting to the magnetic susceptibility showed that an intramolecular antiferromagnetic exchange interaction occurred between iron atoms with J=-25.51 cm^?1, and a weaker intermolecular autiferromagnetic exchange interaction occurred with zJ' = ?2.30 cm^?1.     

Complex Formation Equilibria of Iron(III) With 2-Hydroxy-3- Pyridinol and 2-Mercapto-3-Pyridinol. Spectrophotometry Determination of Iron(III) In Multivitamins

ABSTRACT

The complex equilibria of iron(III) with 2-hydroxy-3-pyridinol (HHP), and 2-mercapto-3-pyridinol (MHP) were studied spectrophotometrically in 40% (v/v) ethanol and an ionic strength of 0.1M (NaCIO₄). The complexation reactions were demonstrated and characterized using graphical logarithmic analysis of the absorbance pH-graphs. After considering all the different parameters a simple, rapid, sensitive and selective method for spectrophotometric determination of trace levels of iron(III) was proposed based on the formation of (Fe -MHP) complex at pH 2.5 (λ_max = 640 nm, ? = l×10⁴ L mol^?1 cm^?). The interference of a large number of foreign ions was investigated. The method has been applied successfully for the determination of iron content in some multivitamins with mineral preparations and infant milk products.