Spectrophotometric study of a ternary zirconium/fluoride/alizarin complex with application to the determination of zirconium

A ternary zirconium/fluoride/alizarin complex is extracted into methyl isobutyl ketone. The apparent molar absorptivity at 556 nm is 1.52 × 10⁵ 1 mol^?1 cm^?1. The r.s.d. is 1.3% for 10 μg Zr (n = 12). There are several interferences, some of which can be masked with EDTA.     

Extraction and Spectrophotometric Determination of Zirconium(IV)

Abstract

A sensitive and selective method for the extraction and spectrophotometric determination of Zr(IV) with N-p-chlorophenyl-3,4-,5-trimethoxycinnamohydroxamic acid (PTCHA) has been developed. The binary complex of Zr(IV)-PTCHA is extracted from 2–6 M HCl into chloroform, having a maximum absorbance at 385 nm; molar absorptivity 2.1 × 10⁴ 1 mol^?1 cm^?1. A ternary complex with xylenol orange (Zr-PTCHA-XO) have been studied in chloroform-ethanol media, which absorbs at 540 nm; molar absorptivity 4.3 × 10⁴ 1 mol^?1 cm^?1. The present method is applied for the analysis of zirconium in standard samples.     

Spectrophotometric Determination of Rhenium(IV) with Thiocyanate,TX-100 and N,N′-Diphenylbenzamidine

A spectrophotometric method to determine rhenium(IV) at trace level is based on the extraction of Re(IV)-SCN^? complex in sulphuric acid media with N,N′-diphenylbenzamidine(DPBA) in presence of a non-ionic surfactant triton X-100 (TX-100) in chloroform. The complex shows maximum absorbance at 435 nm with amolar absorptivity value of 4.24 × 10⁴ L mol^?1 cm^?1 at an acidity range 3.5-6.5 M H₂SO₄. The method followed Beer's Law for the system Re(IV)-SCN^?(TX-100)-DPBA upto 4.0 μg Re(IV) mL^?1. The detection limit of the method is 5 ppb. None of the tested foreign ions, except molybdenum(VI), interfere with the determination of rhenium. The interference due to molybdenum could effectively be removed by prior precipitation with oxine. The effect of various analytical parameters on the extraction of the metal are discussed.     

Spectrophotometric Study of the Effect of Cationic Micelles on the Reaction Between Gallein and Th(IV)

Abstract

The acid dissociation equilibria of gallein (pyrogallolphthalein, gall), as a xanthene dye, in the presence of various surfactants‐cationic, anionic, nonionic, are discussed. The coexistence of a cationic surfactant, such as hexadecyltrimethylammonium chloride (HTAC) slightly enhanced the acid dissociation, and led to a chromogenic reaction between metal ions and gall in weakly acidic media. The ternary complex between gall and Th(IV), in weakly acidic media and in the presence of N-hexadecylpyridinium chloride(HPC), was very stable with definitive spectra. However, the complex was easily decomposed in proportion to the concentration of citrate ion.

Therefore, simple and rapid spectrophotometric methods for the determination of Th(IV) and citrate ion were respectively established, by using the gall-Th(IV)-HPC ternary complex in the cationic surfactant micelle. Beer's law was obeyed over the range 0 to 90 μg of Th(IV) and 12 to 35μg of citrate ion, in a final volume of 10 ml. The Sandell sensitivities were estimated to be 0.0013μg/cm² Th(IV) and 0.0005μg/cm² citrate ion at 600 nm. The analytical procedures were simple and did not require any organic solvent extraction.     

Color Reaction Between 4-(2-Pyridylazo)Resorcinol and Mercury (II) in the Presence of Surfactant,and Improved Spectrophotometric Determinations of Mercury(II) and Cyanide Ion with its Coloring

Abstract

The reactions among 4-(2-pyridylazo)resorcinol (PAR), mercury(II) and/or cyanide ion in the presence of water soluble surfactants alone or combination were systematically investigated at about pH 9. The spectrophotometric determinations of mercury(II) and cyanide ion were investigated by using the PAR-mercury(II)-HPC complex (3:2:2 molar ratio) in the presence of N-hexadecylpyridinium chloride (HPC) alone; calibration graphs were rectilinear in the ranges of 0 – 40 μg mercury(II) and 0 –10 μg cyanide ion in a final 10 ml with the apparent molar absorptivities of 5.9 × 10⁴ for mercury(II) and 2.5 × 10⁴ 1 mol^?1 cm^?1 for cyanide ion at 590 nm. The proposed method had advantages—rapidity, simplicity without solvent extraction, and sensitivity in comparison with reported solvent extraction methods. The interference of foreign ions decreased 1/2–l//4-fold compared with that in the presence of non-ionic surfactant alone.     

Rapid and Sensitive Spectrophotometric Determination of Hafuium(IV) With 2-(5-Bromo-2-Pyridylazo)-5-Diethylaminophenol

Abstract

Hafnium(IV) reacts with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol in the pH range 3.3–11.0 to yield a sparingly soluble red-coloured chelate that can be dissolved with Triton X-100. Effect of initial pH of metal ion and order of addition of reagents was studied in detail. The 1:3 complex adheres to Beer's law over the concentration range 0.02–1.12 μg/ml of Hf(IV), has a molar absorptivity 1.33x10⁵ 1 mol^?1cm^?1, Sandell sensitivity 1.3 ng cm^?2, formation constant (log K) 11.94 and the method had a relative standard deviation of ± 1.5%. Effect of 60 diverse ions on the determination of hafnium(IV) was studied. This fairly selective method is the most sensitive so far reported for the spectrophotometric determination of hafnium(IV).     

Extraction,Spectrophotometric, and Atomic Absorption Spectrophotometric Determination of Selenium With N-Phenylbenzohydroxamic Acid

Abstract

Solvent extraction spectrophotometric and atomic absorption spectrophotometric methods for the determination of selenium(IV) in microgram quantities are described. The selenium(IV) forms yellow colored complex with N-phenylbenzohydroxamic acid (PBHA) extractable into chloroform from 7 M HClO₄. Se-PBHA complex has maximum absorbance at 345 nm with a molar absorptivity 1.5 × 10⁵ 1 mol^?1 cm^?1 and Sandell's sensitivity 0.000526 μg /cm². Effect of molarity, reagent concentration, diverse ions on the extraction of selenium complex were studied. The selenium is determined in presence of tellurium.     

Microdetermination of acetone in aqueous solution

Diazotized anthranilic acid has been found to be a possible reagent for the spectrophotometric microdetermination of acetone in aqueous solution. The determination range is 10–130 μg/ml. The coefficient of variation does not usually exceed 12% for 60–130 μg of acetone but increases to 2.8% at the 10-μg level. The average relative error for five determinations ranges from ?1.5 to 2%. The molar absorptivity is 9.28 × 10³ liter · mol^?1 · cm^?1 in the presence of starch as a surfactant. Possible reaction path mechanism has been suggested for the colored body formation.     

Spectrophotometric determination of silver with 4-(3,5-dibromo-2-pyridylazo)-N,N-diethylaniline in the presence of sodium dodecylsulfate

The bidentate ligands, 4-(3,5-DiBr-PAEA) and 4-(3,5-DiBr-PAESA) react with silver(I) ion to form the Agl2 chelate in the presence of anionic or nonionic surfactant. The molar absorptivity at 600 nm is 80 000 l mol^?1 cm^?1 in 0.1% sodium dodecylsulfate solution. Optimum conditions for the spectrophotometric determination of silver in the range 0.1–1.0 mg l^?1 with 3,5-diBr-PAEA are reported. A flow-injection procedure is also presented.     

Spectrophotometric determination of iron(III) with EDTA tetrahydrazide

The tetrahydrazide of ethylenediamine tetraacetic acid (NH₂NH)₄-EDTA was synthesized from the EDTA ester and hydrazine hydrate in ethanolic solution, the resulting (NH₂NH)₄-EDTA being recrystallized in 60% ethanol. When the spectrophotometric study of the iron(III) (NH₂NH)₄-EDTA complex in aqueous solution was made two absorption maxima at 530 and 450 nm at pH 4.5 and 11.0, respectively, were found. Beer's law is obeyed in the range 1.0–20.0 μg Fe(III) ml^?1 at 530 nm and pH 4.5 and 0.5–12.0 μg Fe(III) ml^?1 at 450 nm and pH 11.0, the molar absorptivities being 1.95 × 10³ 1 mol^?1 cm^?1 at 530 nm and 3.35 × 10³ 1 mol^?1 cm^?1 at 450 nm, respectively. The Ringbom optimal interval falls between about 3 and 18 μg Fe(III) ml^?1 at 530 nm and about 2–14 μg Fe(III) ml^?1 at 450 nm. The reaction between the metal and the ligand was also investigated. The method has been successfully applied to the determination of iron in talcs.     

Spectrophotometric determination of zirconium with alizarin red S in the presence of polyvinylpyrrolidone

The absorbance of the microcolloidal zirconium/alizarin red S/polyvinylpyrrolidone complex is measured at 525 nm in acetate buffered medium at pH 4.75. The molar absorptivity is 3.8 × 10⁴ l mol^?1 cm^?1, which is much greater than that of the classical method. Sulphate and fluoride do not interfere.     

Extraction-photometric determination of uranium(IV) with chlorophosphonazo-III

A sensitive spectrophotometric method has been developed for the determination of uranium. The uranium(IV)-chlorophosphonazo-III complex is extracted into 3-methyl-1-butanol from 1.5–3.0 M hydrochloric acid solution. Maximal absorbance occurs at 673 nm and Beer's law is obeyed over the range of 0–15 μg per 10 ml of the organic phase. The molar absorptivity is 12.1·10⁴ 1 mole^?1 cm^?1. Uranium can be determined in the presence of fluoride. sulfate and phosphate. Nitrate ion and elements (chromium, copper, iron) which affect the reduction of uranium(VI) or stability of uranium(IV) interfere.     

Solvent extraction and spectrophotometric determination of titanium(IV) with 3-phenyl-3-methyl-2-mercaptopropenoic acid

The distribution equilibria of 3-phenyl-3-methyl-2-mercaptopropenoic acid (PhMMP) and the titanium(IV)-PhMMP complex have been studied. An extraction-photometric method for the determination of microamounts of titanium has been developed. We have investigated the influence of pH, the reagent, and the presence of electrolytes and masking agents in the aqueous phase on the equilibrium. From the slope analysis of the distribution curves the composition of the extracted species has been found to be Ti(OH)₂(HR)₂. The complex is extracted quantitatively. Beer's Law is followed over the range 0.09–3.74 μg ml^?1 of titanium(IV), the molar absorptivity is 1.65 × 10⁴ liters mol^?1 cm^?1, and the Sandell sensitivity is 2.8 ng cm^?2 at 439 nm. This method has been applied to the determination of titanium in a bauxite.     

Spectrophotometric determination of osmium with phthalimide dithiosemicarbazone by means of complex formation and catalytic reactions

Phthalimide dithiosemicarbazone forms a 1:1 complex with osmium at pH 3.3–4.5 (?₄₅₀ = 1.3 · 10⁴ l mol^?1 cm^?1 ) which is applied to the photometric determination of osmium; Beer's law is obeyed for the range 1–12 μg Os ml^?1. The oxidation of the reagent with cerium(IV) is catalyzed by osmium(VIII), and this reaction allows a more sensitive procedure for the determination of osmium; the calibration curve is linear over the range 0.05–0.4 μg Os ml^?1. The interferences in both procedures are described.     

Preconcentration procedure for determining trace amounts of Ni,Cd, Pb and Cu in high-salinity waters after cloud-point extraction

A procedure for determination of Cd, Pb, Cu and Ni in high-salinity waters by inductively coupled plasma optical emission spectrometry has been developed. It is based on cloud-point extraction of these metals as complexes of diethyldithiocarbamate (NaDDTC) in micellar media of non ionic surfactant octylphenoxypolyethoxyethanol (Triton X-114). Multivariate optimisation techniques have been applied to optimise the experimental variables. A full two-level factorial design was used to evaluate the influence of variables and Doehlert design was performed to find the optimum values. The effect of interference from residual salinity in surfactant-rich phase was also investigated. The developed procedure allows to achieve enhancement factors of 20.0, 20.4, 19.5 and 20.6, along with limits of detection (3σ _B) of 0.030, 2.1, 0.62 and 0.27 µg L^?1, and precision expressed as relative standard deviation (%RSD, n = 10) of 3.7 (40.0 µg L^?1), 5.7 (20.0 µg L^?1), 6.6 (20.0 µg L^?1) and 3.1% (10.0 µg L^?1) for Cd, Pb, Cu and Ni, respectively. The accuracy was evaluated by spike tests on the seawater (salinity of 35‰) and petroleum produced formation waters (salinity between 15‰ and 75‰). It was obtained by recoveries between 79% and 105%.     

Spectrophotometric determination of nitrite with p-nitroaniline and 2-methyl-8-quinolinol in hexadecyl-trimethylammonium bromide solution

Nitrite ion at low concentrations is determined spectrophotometrically by diazotization of p-nitroaniline and coupling of the diazonium salt with 2-methyl-8-quinolinol. The resulting dye is solubilized in hexadecyltrimethylammonium bromide micelles. The molar absorptivity is 4.72 × 10⁴ l mol^-1 cm^-1, and the Sandell sensitivity is 9.7 × 10^-4 μg cm^-2. Some interferences are reported, and preconcentration by evaporation is evaluated. The solubility of hexadecyltrimethylammonium bromide in water was determined as a function of temperature; the Krafft point is 19.6°C. Salting-in of the surfactant by potassium nitrate is described.     

O. Carboxyphenylhydrazoethylacetoacetate as an Analytical Reagent for the Determination of Cu(II) and Co(II) in Complex Materials

An extraction‐spectrophotometric method for the determination of trace amounts of copper and cobalt based on their extraction into n‐pentanol with 0. carboxyphenylhydrazoethylacetoacetate (O.CPHEAA) was per formed. Copper was extracted from pH 6.0 – 8.0 and ionic strength 0.5 M – KCl. The maximum absorption of the extracted Cu(II) ‐ O.CPHEAA complex (1:1 & 1:2 species) occurs at 415 nm. The proposed method succeeded in as saying a concentration of 3–63 μg per 10 mL of n‐pentanol (? = 1.25 × 10⁴L mol^?1 cm^?1). The method failed to ex tract cobalt ion into various organic sol vents over a pH range of 2–11. The suggested method is highly selective and sensitive according to a wide scheme of interference studied. Copper in some plant samples was accurately estimated using the suggested method. The obtained results and the results of the AAS method were consistent. The reproducibility test shows a relative standard deviation of 1%. Sandell sensitivity for A = 0.001 is 5 × 10^?3 μg cm^?2.     

Spectrophotometric determination of platinum with substituted pyrimidine-2-thiol

The yellow complex of Pt(IV) with 1-pyridyl-4,4,6-trimethyl-1H,4H-pyrimidine-2-thiol (PyTPT) which has maximum absorbance at 430 nm, is studied for the spectrophotometric determination of the metal. Molar absorptivity is 5000 liters mol^?1 cm^?1 and Sandell's sensitivity is 0.039 μg/cm². The determination of Pt(IV) (2.8–8.4 ppm) in the presence of diverse ions is described.     

An inimitable and ecological pleasant technique for the assessment of trace amount of copper (II) in tangible samples with new complexing reagent

A simple and rapid spectrophotometric technique has been designed for the trace copper analysis employing 1-(2-Thiazolylazo)-2-naphthol (TAN) reagent in aqueous micellar solution of cetyl trimethylammonium bromide (CTAB) as a surfactant. Copper complexed with 1-(2-Thiazolylazo)-2-naphthol to form bis[1-(2-Thiazolylazo)-2-naphthol]copper. The present spectrophotometric technique was very important since the micellar system was used in place of the toxic, high cost and time-consuming solvent extraction steps. The technique showed an enhanced detection efficiency, specificity, and molar absorptivity. It was found that the molar absorption coefficient and sensitivity of Sandel were ε 2.45 × 10⁴ L mol^?1cm^?1 and 2.6 ngcm^?2 at λ_max 578.4 nm. A linear calibration plot in the range 0.12–5.0 μg mL^?1 was obtained; a stoichiometric metal ligand ratio [M:L] of 1:2 was found for the formation of Cu-[TAN]₂. The complex was formed at pH 9.5 and was stable up to 24 h. The proposed technique has been employed to study copper from different alloys, biological, environmental and pharmaceutical samples.     

Absorption Spectra of 4f Electron Transitions of Neodymium and Erbium with 8-Hydroxyquinoline-5-sulphonic Acid and Diethylamine Systems and Its Analytical Application

Abstract

In this paper the absorption spectra of 4f electron transitions of the systems of neodymium and erbium with 8-hydroxyquino-line-5-sulphonic acid and diethylamine have been studied by normal and third-derivative spectrophotometry. Their molar absorptivities are 80 l.mol^?1.cm^?1 for neodymium and 65 l.mol^?1.cm^?1 for erbium. Use of the third-derivative spectra, eliminates the interference by other rare earths and increases the sensitivity for Nd and Er. The derivative molar absorptivities are 390 1.mol^?1.cm^?1 for Nd and 367 1.mol^?1.cm^?1 for Er. The calibration graphs were linear up to 11.8 μg/ml of Nd and 12.3 μg/ml of Er, respectively. The relative standard deviations evaluated from eleven independent determinations of 7.2 μg/ml (for Nd) and 8.3 μg/ml (for Er) are 1.3% and 1.4%, respectively. The detection limits (signal to noise ratio = 2) are 0.2 μg/ml for Nd and 0.3 μg/ml for Er. The method has been developed for determining those two elements in mixture of lanthanides by means of the third-derivative spectra and the analytical results obtained are satisfactory.