New Spectrophotometric Method for the Determination of Titanium in Soil and Standard Geochemical Samples

Abstract

In the present communication a simple and rapid spectrophotometric method for the determination of titanium is described. The method is based on the reaction of Ti(IV) with a newly synthesized reagent, 6-(4-nitrophenylazo)-3,4,5-trihydroxy benzoic acid (NATHB), in ethanol medium at pH 3.2 to 4.2. The complex exhibits an absorption maximum at 495 nm and Beer's law is valid over the range of 0.04 – 1.00 μg.ml^?1 Ti. The molar absorptivity is 3.48 × 10⁴ dm³.mole^?1. cm^?1. Most of the foreign metal ions and anions do not produce any colorations with NATHB at selected conditions. Based on these results, a simple and direct spectrophotometric method with high selectivity and sensitivity was proposed. The method has been successfully applied for the determination of titanium in 5 soil and 3 standard geochemical samples.     

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.     

Spectrophotometic Determination Of Tin In Steels With2-(5-Nltro-2-Pyridylazo)-5-[N-n-Propyl-N-(3-Sulfopropyl)Amino]phenol

ABSTRACT

A highly sensitive azo dye, 2-(5-nitro-2-pyridylazo)-5-[N-n-propyl-N-(3-sulfopropyl)amino]phenol (Nitro-PAPS), is used as a colorimetric reagent for the determination of tin(IV) content. Nitro-PAPS reacts with tin(IV) to form a water-soluble complex in 1.0 M acetic acid. Full color development is attained within 5 minutes, and maintains constant absorbance for at least 24 hours. The apparent molar absorptivity is 7.7 x 10⁴ dm³ mol^?1 cm^?1 at a maximum wavelength of 580 ran. Beer's law is obeyed for tin(IV) in the range of 0-1.2 μg ml^?1. The proposed method is successfully applied to the determination of trace amounts of tin in steels.     

The kinetics of complex formation between Ti(IV) and hydrogen peroxide

The kinetics of the formation of the titanium‐peroxide [TiO²⁺₂] complex from the reaction of Ti(IV)OSO₄ with hydrogen peroxide and the hydrolysis of hydroxymethyl hydroperoxide (HMHP) were examined to determine whether Ti(IV)OSO₄ could be used to distinguish between hydrogen peroxide and HMHP in mixed solutions. Stopped‐flow analysis coupled to UV‐vis spectroscopy was used to examine the reaction kinetics at various temperatures. The molar absorptivity (ε) of the [TiO²⁺₂] complex was found to be 679.5 ± 20.8 L mol^?1 cm^?1 at 405 nm. The reaction between hydrogen peroxide and Ti(IV)OSO₄ was first order with respect to both Ti(IV)OSO₄ and H₂O₂ with a rate constant of 5.70 ± 0.18 × 10⁴ M^?1 s^?1 at 25°C, and an activation energy, E_a = 40.5 ± 1.9 kJ mol^?1. The rate constant for the hydrolysis of HMHP was 4.3 × 10^?3 s^?1 at pH 8.5. Since the rate of complex formation between Ti(IV)OSO₄ and hydrogen peroxide is much faster than the rate of hydrolysis of HMHP, the Ti(IV)OSO₄ reaction coupled to time‐dependent UV‐vis spectroscopic measurements can be used to distinguish between hydrogen peroxide and HMHP in solution. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 457–461, 2007     

Selective Spectrophotometric Determination of Palladium (II) With 2-(5-Bromo-2-Pyridylazo)-5-(Diethylamino)-Phenol

Abstract

A spectrophotometric study of the Pd(II) complex of a reagent 2-(5-Bromo-2-Pyridylazo)-5-(diethylamino)-Phenol (5-Br-PADAP) is presented. A violet complex is formed at pH 3.53, and shows maximal absorbance at 585 nm with molar absorptivity of 3.86 × 10⁴ 1. mol^?1 cm^?1. Beer's law is obeyed up to 50 μ of Pd(II). The method offers the advantages of simplicity, high precision, requires no extraction and is very selective, where 5.0 mg Pt(VI) and 0.3 mg Au(III) ions do not interfere.     

Xylenol Orange,Zirconium(IV) and Fluoride Color Reaction in Mixed Micelles of N-Hexadecylpyridinium Chloride and Brij 35, and Its Analytical Application1

Abstract

The color reaction between Xylenol orange (XO), zirconium (IV) and fluoride ions in the presence of various surfactants alone or in combination was studied at various pH. The XO -zirconium)IV)-fluoride ion ternary complex in mixed micellar media containing a low concentration of N-hexadecylpyridinium chloride (HPC) as a cationic surfactant and large amounts of (poly{oxyethylene)dodecyl ether (Brij 35) as a nonionic surfactant at weakly acidic media was found to be the most stable, and showed a remarkable bathochromic shift and clear contrast against a reagent blank. The maximum absorbance was at 600 nm in the mixed micellar media at pH 3.5, and the apparent molar absorptivities at 600 nm were 7.0 × 10⁴ 1 mol^?1 cm^?1 for zirconium(IV) and 1.4 × 10⁴ 1 mol^?1 cm^?1 for fluoride ion. The calibration curves covered the ranges of 0.5 ～ 20.0 μg/10 ml zirconium! IV) and 0 ～ 20.0 μg/10 ml fluoride ion with the Sandell sensitivities being 0.0013 μg/cm² for zirconium(IV) and 0.0016 μg/cm² for fluoride ion.     

Determination of Vanadium with Chlorosubstituted Hydroxamic Acids for Photometric and Atomic Absorption Spectrophotometric Determination

Abstract

The eight newly synthesized chlorosubstituted hydroxamic acids are described for the extraction and spectrophotometric determination of vanadium. The sensitive and selective reagent, N-m-Chlorophenylpalmito hydroxamic acid, (m-CPPHA), which gives violet coloured vanadium complex was extracted with chloroform from 6M HCl. The violet coloured complex thus obtained has a maximum absorbance at 520 nm and molar absorptivity 4.9 ± 10³1mol^?1cm^?1. The Beer's law obeyed in the region 0.50-12.0ppm. Effects of acidity, reagent concentration, diverse ions have also been investigated. A comparison has been made with atomic absorption spectrophotometric method. Vanadium has been determined in the environment, e.g. plant, soil, rock, etc.     

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).     

Spectrophotometric Determination of Trace Amounts of Ascorbic Acid

Abstract

Colourless silver-gelatin complex is quantitatively reduced by ascorbic acid to yellow silver sol in water within the pH range 7.5–10.0 at room temperature. The determination of 1–10μg/ml of ascorbic acid is possible at 415 nm in the presence of glycine, alanine, fructose, sucrose, citric, tartaric, oxalic, malic, succinic acids and also in the presence of various reducing agents. The molar absorptivity of ascorbic acid at the δ_max is found to be 21500 lit mol^?1 cm^?1 and the Sandell sensitivity of the sol is 8.18x10^?3 μg ascorbic acid cm^?2 for 0.001 absorbance. The relative standard deviation is ±0.22% and the confidence limit (20 determinations, 95%) being 8.806±0.0093%.     

Complexation of Osmium(IV) with 3-Methyl-2,6-Dimercapto-1-Thiopyrone-4 and Its Catalytic Application

The reaction of osmium(IV) with 3-methyl-2,6-dimercapto-1-thiopyrone-4 was studied by spectrometry, amperometry, and potentiometry. In a pH range of 2–4 M HCl (2 M H₂SO₄), insoluble osmium methyl thiopyrone dimercaptides formed with a metal-to-ligand ratio of 1 : 1, 1 : 2, 1 : 3, 1 : 4, and 1 : 6 in HCl solutions and of 1 : 1, 1 : 2, 1 : 3, and 1 : 5 in H₂SO₄ solutions. Conditional stability constants and molar absorption coefficients were determined for the products formed in the presence of excess reagent (n = 3, P = 0.95): logβ = 24.42 ± 0.02 and ε = (2.95 α 0.01) × 10⁴ for the 1 : 5 complex and logβ = 30.24 ± 0.10 and ε = (2.92 ± 0.01) × 10⁴ for the 1 : 6 complex. It was shown that the reagent can be used for the potentiometric titration of osmium(IV). Conditions were determined for the successive titration of components of the osmium(IV)-ruthenium(IV) mixture.     

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.     

Rapid Extraction Spectrophotometric Determination of Platinum Using Anisaldehyde-4-Phenyl-3-Thiosemicarbazone as a Chromogenic Reagent

Abstract

The synthesis, spectral characteristics and analytical applications of anisaldehyde-4-phenyl-3-thiosemicarbazone (APT) are described. A simple, rapid, selective and sensitive spectrophotometric method for the determination of platinum was developed based on the colour reaction between platinum (IV) and anisaldehyde-4-phenyl-3-thio-semicarbazone (APT) in the pH range 1.7 - 3.0. The yellow coloured species has an absorption maximum at 360 nm. The complexation is complete within 1 min. A five-fold excess of the reagent is required for complete complex formation. Beer's law is obeyed over the concentration range 0.1 -20 ppm of Pt(IV). The mtilar absorptivity and Sandell's sensitivity are 1.58 × 10⁴ l. mol^?1 cm^?1 and 0.0123 ug of Pt(IV) cm^?2, respectively. The effects of pH, time concentration of reagent, order of addition of reagents and the interference from various ions were investigated. The method has been employed for the determination of platinum in synthetic mixtures whose composition correspond to some alloys.     

Indirect Spectrophotometric Determination of Vanadium(IV) by Flow Injection Analysis Based on the Redox Reaction with Copper(II) in the Presence of Neocuproine

Abstract

An indirect photometric method with a continuous-flow analysis is presented for the determination of trace amounts of vanadium(IV). It is based on the redox reaction of copper(II) with vanadium(1V) in the presence of neocuproine. In the presence of neocuproine, copper(I1) is reduced easily by vanadium(I V) to a copper(1)-neocuproine complex, which shows a n absorption maximum at 454 nm. By measuring t h e absorbance of the complex at this wavelength, vanadium(1V) in t h e range 2×10^?6 - 8 × mol dm^?5 mol dm^?3 can be determined at a rate of 120 samples h^?1. The fractional determination of vanadium(1V) and iron(I1) is also studied.     

Novel Method for Selective Spectrophotometric Determination of Titanium(IV) with Water Extract of Slippery Elm Leaf as a New Reagent

Abstract

A novel spectrophotometric method for the determination of titanium(IV) by using a new reagent, water extract of slippery elm leaf is developed. In 0.05 M hydrochloric acid, titanium(IV) reacts with this reagent to form a yellow product. The formed product shows maximum absorbance at 415 nm with a molar absorptivity value of 0.68×10⁴ l mol^–1 cm^–1 and the method was linear in the 0.2–6 µg ml^?1 concentration range. The detection limit value was found to be 0.0131 µg ml^?1. The proposed method was simple, low cost, selective, and sensitive. It was applied to the analytic samples with satisfactory results.     

Study on Complex of Re(III) with 3, 5-Br2-DMPAP by Electrochemistry and Application

ABSTRACT

The electrochemical character of a new reagent, 2-(3, 5-Dibrome-2-pyriclyiazo)-5-dimethylaminophenol(3, 5-Br₂-DMPAP) was studied in HAc-NaAc medium at pH=3.50. In single sweep polarography, the reduction potential of the complex wave (-1.05V) is more negative than that of the free ligand(-1.01V). The complex wave was proven to be an adsorption wave. The composition ratio of the complex was formed to be 1:1 using a molar ratio method. The current of the adsorptive peak at-1.05V was directly proportional to the concentration of Re(III) in the range of 1.5× 10^?8～7.0×10^?5mol/l. The microamount of Re in several samples of Chinese cigarettes determined with satisfactory accuracy and precision.     

Hydroxy Naphthol Blue as a Spectrophotometric and Fluorometric Reagent for the Uranyl Ion

Abstract

The utility of hydroxy naphthol blue (HNB) as a spectrophotometric and fluorometric reagent for the uranyl ion has been investigated. In phthalate buffer (at a pH of 4.0), UO₂ ²⁺ forms a brown complex of low absorptivity with the red form of HNB. By following the decrease in HNB absorbance at 530 nm (which has ε = 4.1 × 10³) uranyl ion can be determined to levels as low as 1.1 × 10^?6 M (0.30 μg/ml). HNB also emits at 460 nm when excited at 365 nm at these pH values, while the UO₂ ²⁺ complex exhibits greatly reduced emission. Examination of the quenching of HNB emission by UO₂ ²⁺ allows the determination of uranyl ion to levels as low as 3.2 × 10^?6 M (0.86 μg/ml). A 1:1 type complex was formed between UO₂ ²⁺ and HNB, and a formation constant of 9.77 × 10³ (log K₁ = 3.99) was measured for the complex.     

Spectrophotometric Determination of Sulphathiazole

Abstract

A new, rapid, simple, selective and sensitive method for the spectrophotometric determination of sulphathiazole is described. The drug forms a yellow coloured complex with Pd(II) in alkaline medium (1 M NaOH). The drug complex exhibits maximum absorbance at 410 nm, with a molar absorptivity of 1.9 × 10³ 1 mol^?1 cm^?1. Effects of molarity of NaOH, reagent concentration on the proper complex formation are discussed. The system obeys Beer's law in the concentration range of 10-160 ppm of sulphathiazole.     

Column Chromatographic Preconcentration of Copper in Alloys and Complex Materials Using 9,10 Phenanthrenequinone Monoxime Supported on Naphthalene

Abstract

A solid chelating compound phenanthrenequinone monoxime PQM) supported on naphthalene provides a rapid and economical means of preconcentration and separation of copper from the aqueous samples. Copper forms a complex with PC:: supported on naphthalene in the column at pH 6.1–8.4 with a flow rate of 1 ml/min. The metal complex and naphthalene are dissolved out from the column with 5 ml of DMF and the absorbance is measured at 470 nm against reacent blank. Beer's law is obeyed in the concentration range 0.6 9.6 μg of copper in 5 ml of DMF. The molar absorptivity and sensitivity are 6.3×10⁴ L mol^?1 cm^?1 and 0.001 μg cm^?2 respectively.     

THE INTERACTION OF 2-AMINO-2-HYDROXYMETHYL-1,3-PROPANEDIOL WITH COBALT(II) AND MANGANESE(II) IONS

Abstract

The stepwise complex formation between 2-amino-2-hydroxymethyl-1,3-propanediol (TRIS) with Co(II) and Mn(II) was studied by potentiometry at constant ionic strength 2.0 M (NaClO₄) and T = (25.0 ± 0.1)°C, from pH measurements. Data of average ligand number (Bjerrum's function) were obtained from such measurements followed by integration to obtain Leden's function, F ₀(L). Graphical treatment and matrix solution of simultaneous equations have shown two overall stability constants of mononuclear stepwise complexes for the Mn(II)/TRIS system (β₁ = (5.04 ± 0.02) M^?1 and β₂ = (5.4 ± 0.5) M^?2) and three for the Co(II)/TRIS system (β₁ = (1.67 ± 0.02) × 10² M^?1, β₂ = (7.01 ± 0.05) × 10³ M^?2 and β₃ = (2.4 ± 0.4) × 10⁴ M^?3). Slow spontaneous oxidation of Co(II) solutions by dissolved oxygen, accelerated by S(IV), occurs in a buffer solution TRIS/HTRIS⁺ 0.010/0.030 M, with a synergistic effect of Mn(II).     

Extraction and spectrophotometric determination of trace amounts of tin(II) with diphenylglyoxal bis(2-hydroxybenzoylhydrazone)

Diphenylglyoxal bis(2-hydroxybenzoylhydrazone) has been used as a sensitive reagent for the spectrophotometric determination of tin. This reagent forms an orange-yellow complex with stannous ion at pH 3.5–7.0 (λ_max = 455 nm, ? = 2.25 × 10⁴ liter mol^?1/cm^?1 while no reaction is observed with quadrivalent tin. The colored complex extracted into isobutyl methyl ketone has been used for the spectrophotometric determination of trace amounts of tin(II). The molar absorption in the organic solvent is 3.54 × 10⁴ liter mol^?1 cm^?1 and the compound shows its maximum absorbance at 455 nm. The interferences of foreign ions have been determined.