A new sensitive spectrophotometric determination of sodium 2-mercaptoethanesulfonate using leuco xylene cyanol FF

A simple and accurate spectrophotometric method for determination of sodium 2-mercaptoethanesulfonate (MESNa) with leuco xylene cyanol FF (LXCFF) has been developed. The proposed method is based on the reaction of MESNa with potassium iodate(V) in acidic medium to liberate iodine, which oxidizes leuco xylene cyanol FF to its blue form xylene cyanol FF. The xylene cyanol FF dye formed shows maximum and stable absorbance at pH 4.1–4.2. Absorbance of the obtained colored products was measured at 613 nm. The molar absorptivity, limit of detection and limit of determination of the method were found to be 3.64 × 10⁴ L/mol cm, 0.29 and 0.33 μg/mL, respectively. The colour system obeys Beer’s laws in the range 0.4–4.0 μg/mL of MESNa. All the variables were studied in order to optimize the reaction conditions. The procedure was used for determination of MESNa in pharmaceutical preparations. Reliability of determination was confirmed applying standard iodometric method, recommended by European and Polish Pharmacopoeia.     

Rapid and sensitive spectrophotometric determination of trace amounts of iron(III) using leuco Xylene cyanol FF

A new, simple, sensitive, and reliable method is presented for the rapid spectrophotometric determination of trace amounts of iron(III) using leuco Xylene cyanol FF. The method is based on the oxidation of leuco Xylene cyanol FF (LXCFF) to its blue form of xylene cyanol FF by iron(III) in sulfuric acid medium (pH 2.0–3.0), the absorbance of the formed dye is measured in an acetate buffer medium (pH 2.8–4.4) at 615 nm. The method obeys Beer's law over a concentration range of 0.15–0.9 g mL^-1 iron, having a molar absorptivity of 5.6×10⁴ L mol^-1 cm^-1 and a Sandell's sensitivity of 0.0001 g cm^-2. The optimum reaction conditions and other analytical parameters have been evaluated. The developed method has been successfully applied to the determination of iron in water, soil, industrial effluent, plant material, pharmaceutical preparations, synthetic mixtures, and aluminum alloys.     

Synergic extraction and spectrophotometric determination of titanium(IV)

A method has been developed for the synergic extraction and spectrophotometric determination of Ti(IV) with N-hydroxy-NN'-diphenylbenzamidine and thiocyanate. The yellow ternary complex, extracted into chloroform from dilute sulphuric acid medium (pH = 1.5+/-0.1), has maximum absorbance at 390 nm (molar absorptivity 1.3 x 1O(4) 1.mole(-1). cm(-1)). The method is free from interference from a large number of foreign ions and is recommended for the determination of titanium in steel.     

Simultaneous determination of trace iron and aluminum by catalytic spectrophotometry based on a novel oxidation reaction of xylene cyanol FF.

A new, simple, sensitive and selective method for the simultaneous determination of trace iron and aluminum by catalytic spectrophotometry was presented, based on the catalytic effects of iron and aluminum on the discoloring reaction of xylene cyanol FF proceeded by hydrogen peroxide and potassium periodate in weak nitric acid medium. No catalytic effect was obtained in the presence of hydrogen peroxide or potassium periodate only. With the conditional rate constants determined in reaction systems catalyzed by Al or Fe only, the concentrations of Fe and Al in the samples can be calculated. The method was applied to the simultaneous determination of trace Fe and Al in tap water, lake water, river water and tea leaves without separation and preconcentration.     

Study of 2-(2-quinolinylazo)-5-dimethylaminobenzoic acid as a new chromogenic reagent for the spectrophotometric determination of cobalt

2-(2-Quinolinylazo)-5-dimethylaminobenzoic acid (QADMAB) is proposed as a new sensitive and selective chromogenic reagent for spectrophotometric determination of cobalt. The QADMAB reacts with cobalt in the presence of cetyl trimethylammonium bromide (CTMAB) medium to form a violet complex of molar ratio 1:2 (cobalt to QADMAB) in the pH range 3.2-5.2. The molar absorptivity of the complex is 1.28x10(5) L mol(-1) cm(-1) at 625 nm. Beer's law is obeyed in range 0.01-0.32 micro g mL(-1). The relative standard deviation for eleven replicate samples of 0.2 micro g mL(-1) is 0.76%. This method was applied to the determination of cobalt in biological samples, Vitamin B(12), alloys and water with good results.     

Spectrophotometric determination of thorium in standard samples and monazite sands based on the floated complex of thorium with N-hydroxy-N,N′-diphenylbenzamidine and thorin

A selective and sensitive spectrophotometric method for the determination of Th(IV) has been based on the reaction with thorin and subsequent extraction of the red-orange coloured complex with N-hydroxy-N,N'-diphenylbenzamidine (HDPBA) in benzene as floated complex at pH 2.2. The complex in ethanol exhibits a maximum absorbance at 495 nm, with a molar absorptivity of 6.0x10(4) l mol(-1) cm(-1), with a Sandell's sensitivity of 3.9x10(-3) microg cm(-2). The method follows Beer's law up to 3.0 microg Th(IV) ml(-1). None of the common cations and anions tested interfere. The detection limit of the method is 0.04 microg Th(IV) ml(-1), the RSD (n=10) is 1.4%. The method has been successfully employed for the determination of thorium in various standard and monazite samples.     

On-column complexation and simultaneous separation of vanadium(IV) and vanadium(V) by capillary electrophoresis with direct UV detection

An on-column complexation method has been developed for the simultaneous determination of V(IV) and V(V). Vanadium species were chelated with aminopolycarboxylic acids to form anionic complexes which were separated by capillary zone electrophoresis (CZE) with direct UV detection. Ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentacetric acid (DTPA), nitrilotriacetic acid (NTA), and N-2-hydroxyethylethlendiaminetriacetric acid (HEDTA) were investigated as both ligand and running electrolyte. Of the ligands studied the complexes of EDTA with V(IV) and V(V) resulted in the highest selectivity and UV response.The conditions used for on-column complexation and separation, including pH, and electrolyte ligand concentration, were examined to achieve reasonable separation selectivity and detection sensitivity. The optimum separation of the anionic forms of V(IV) and V(V) was obtained by use of CZE with UV detection at 185 nm and an electrolyte containing 5 mmol L(-1) EDTA at pH 4.0. Linear calibration plots were obtained in the concentration range10-300 micro mol L(-1); detection limits were 3 micro mol L(-1) for V(IV) and 1 micro mol L(-1) for V(V). The proposed method was demonstrated for the determination of vanadium in groundwater spiked with V(IV) and V(V).     

Study of the titanium-phenylfluorone complex formed in the presence of Triton X-305 and emulsifier OP

A highly sensitive method for the spectrophotometric determination of titanium with phenylfluorone (PF) in the presence of Triton X-305 and emulsifier OP has been developed. In acid medium (pH 1.4-2.2) Ti(IV) forms red-violet complexes with PF, Triton X-305 and OP. The complex exhibits maximum absorption at 540 nm. The molar absorptivity is 1.63 x 10(5) 1.mole(-1).cm(-1). The Ti:PF ratio in the complex is 1:2. Beer's law is obeyed in the titanium concentration range 0-0.2 microg/ml in the final solution. Fluoride and EDTA interfere. The method has been used for the rapid direct determination of microamounts of Ti(IV) in soils and cereals with satisfactory results.     

A high-selectivity spectrophotometric reagent for determining platinum(IV)

The new reagent N-(m-Methylphenyl)-N'-(sodium p-aminobenzenesulfonate)-thiourea (MMPT) was synthesized and its structure was confirmed by elemental analysis, IR, UV and (1)HNMR spectra. The apparent molar absorptivities of usual ions were determined and the chromogenic reaction with microamounts of platinum(IV) was studied in detail. In the medium of an HAc-NaAc buffer solution, MMPT can react with platinum(IV) to form a green soluble complex. The maximum absorbance of the complex is at 754.4 nm (epsilon(754.4)=8.58 x 10(4) L.mol(-1).cm(-1)) and 332.8 nm (epsilon(332.8)=1.14 x 10(5) L.mol(-1).cm(-1)). Beer's law was obeyed for platinum concentrations in the range of 0 approximately 1.28 mg.L(-1); the correlation coefficient was r=0.9995. At 754.4 nm, over 50 ions did not interfere with the reaction. It is one of the simplest and most selective methods available. It was convenient and rapid and has been applied to the direct determination of Pt(IV) in ores and catalysts with satisfactory results.     

Low-temperature sorption-luminescence determination of platinum using silica chemically modified with dithiocarbamate groups

Application of silica chemically modified with dithiocarbamate groups (DTCS) has been proposed for the low-temperature sorption-luminescence determination of platinum. The establishment of a sorption equilibrium in the platinum(IV) and platinum(II) extraction with DTCS from hydrochloric acid solutions takes 20 and 2 min, respectively. If the duration of the phase contact is optimal, the recovery achieves 99% in the acidity range from 4 M of HCl to pH 5. The sorption of platinum(IV) and platinum(II) results in the formation of coordination compounds of platinum(II) on the surface of the adsorbent which are luminescent in ultraviolet light when frozen (77 K). A procedure has been developed for low-temperature sorption-luminescence determination of platinum with the detection limit of 0.5 ??g of platinum per 0.1 g of the adsorbent and linearity of the calibration curve to 25 ??g/0.1 g. The developed procedure has been applied to the determination of platinum in the samples of alumoplatinum catalyst.     

Rapid, selective, direct and derivative spectrophotometric determination of titanium with 2,4-dihydroxybenzaldehyde isonicotinoyl hydrazone

A simple and sensitive spectrophotometric method is developed for the determination of titanium in aqueous medium. The metal ion forms a reddish brown coloured complex with 2,4-dihydroxybenzaldehyde isonicotinoyl hydrazone (2,4-DHBINH) in the pH range 1-7. The complex shows two absorption maxima, one at 430 nm and the other at 500 nm. The reagent shows appreciable absorbance of 430 nm and negligible absorbance at 500 nm at pH 1.5. Beer's law is obeyed in the range 0.09 to 2.15 mug ml(-1) of titanium(IV). The molar absorptivity and the Sandell's sensitivity of the method are 1.35 x 10(4) 1 mol(-1) cm(-1) and 0.0049 mug cm(-2), respectively. A method for the determination of titanium by first-order derivative spectrophotometry is also proposed. The methods have been employed successfully for the determination of titanium in several alloy and steel samples.     

Spectrophotometric determination of silver with 2-(2-quinolylazo)-5-diethylaminophenol as chromogenic reagent

A new chromogenic reagent, 2-(2-quinolylazo)-5-diethylaminophenol (QADEAP) was synthesized. A highly sensitive, selective and rapid method for the determination of silver based on the rapid reaction of silver(I) with QADEAP has been developed. In the presence of citric acid-sodium hydroxide buffer solution (pH=5.0) and sodium dodecyl sulfonate (SDS) medium, QADEAP reacts with silver to form a violet complex of a molar ratio 1:2 (silver to QADEAP). The molar absorptivity of the complex is 1.33x10(5) L mol(-1) cm(-1)at 590 nm. Beer' s law is obeyed in the range of 0.01-0.6 micro g mL(-1). The relative standard deviations for eleven replicate samples of 0.2 microg mL(-1) is 1.38%. This method was applied to the determination of silver in water with satisfactory results.     

Amperometric titration of palladium, silver and copper with benzimidazol-2-ylmethanethiol, and its application to non-ferrous materials

A method is described for the determination of mg amounts of palladium, silver and copper by amperometric titration with benzimidazol-2-ylmethanethiol in acetate buifer medium (pH 4-5) at an applied potential of -0.2 V vs. the saturated calomel electrode. Direct titrations are possible in the presence of a number of foreign ions. Copper and palladium interfere mutually and in the determination of silver. Mercury(I), mercury(II) and platinum(IV) also interfere. Silver does not interfere in the determination of copper and palladium if it is first precipitated as chloride. The method has been successfully applied to the analysis of non-ferrous materials.     

Synthesis and characterization of 1,2-cyclohexanedione bis-benzoyl-hydrazone and its application to the determination of ti in minerals and rocks

The synthesis, spectroscopic characteristics and analytical applications of 1,2-cyclo-hexanedione bis-benzoylhydrazone are reported. The reaction of this new compound with titanium(IV) has been studied spectrophotomelrically. An orange 1:2 metal/ligand complex (lambda(max)= 477 nm, = 1.05 x 10(4) l.mole(-1).cm(-1)) is formed at pH 1.75-3.0 in 3:2 v v ethanol-water medium. The method is simple and selective and has been satisfactorily applied to the determination of titanium in bauxite, Portland cement, amphibolites and granites.     

A highly sensitive colour reaction for Se(IV) with the iodide-rhodamine B-PVA system Spectrophotometric determination of trace amounts of selenium in water

A highly sensitive spectrophotometric method for determination of selenium(IV) has been developed, based on Se(IV) oxidation of I(-) to I(-)(3) in a weak-acid medium, then formation of the 1:1 ion-association complex of I(-)(3) with Rhodamine B in the presence of poly(vinyl alcohol). The molar absorptivity is 1.97 x 10(5)l.mole(-1).cm(-1). Preconcentration of Se(IV) and elimination of interfering ions is achieved by an improved thiol cotton method, so the determination has very good selectivity. Se(IV) at mug/l. levels in tap water, hot-spring water and river water has been satisfactorily determined by the method.     

Acenaphthenequinone monoxime(AQM) as a selective reagent for the spectrophotometric determination of platinum(IV) by solvent extraction

Acenaphthenequinone monoxime has been found to be a selective reagent for spectrophotometric determination of 1-16 ppm of platinum in the pH range 1.90-3.20. With excess of the reagent, a 1 : 2 (metal : ligand) complex is formed with an absorption maximum at 390 nm and molar absorptivity of 9.0 x 10(3) 1.mole(-1).cm(-1). The effect of foreign ions has been investigated and other platinum metals do not interfere if present in similar amounts to the platinum.     

Extraction and separation studies of platinum(IV) with N-n-octylaniline

N-n-octylaniline in xylene is used for the extractive separation of platinum(IV) from acidic media. Platinum(IV) was extracted quantitatively with 10 ml of 3% reagent in xylene from 0.5 to 10 and 2.5 to 10 M hydrochloric and sulphuric acid, respectively. It was stripped from organic phase with water and estimated photometrically with stannous chloride. The effect of metal ion, acids, reagent concentration and of various foreign ions has been investigated. The method affords binary separation of platinum(IV) from iron(III), cobalt(II), nickel(II) and copper(II), and is applicable to the analysis of synthetic mixtures and alloys. The method is fast, accurate and precise.     

Rapid spectrophotometric method (aqueous and extractive) for the determination of titanium in silicate rocks

A sensitive and highly selective aqueous as well as extractive spectrophotometric method has been developed for the determination of titanium(IV) using 2,3-dihydroxynaphthalene (H(2)ND) as a chromogenic agent. The reagent (H(2)ND) forms a 1:3 (TiOH(3+):ligand) complex at pH 4-9. The molar absorptivity and Sandell's sensitivity are 3.2 x 10(4) l . mol(-1)mol . cm(-1) and 0.001 microg/cm(2), respectively at lambda(max) 375 nm. The method has been found highly selective for Ti(IV) determination in rock samples. Solvent extraction of Ti(IV) in ethylacetate greatly improves the detection limit of the method. The method has been successfully applied to diverse silicate rock samples and results obtained are favourably comparable with those obtained from the tiron method. The reagent (H(2)ND) used in the present investigation is a much better variant than tiron for titanium(IV) determination in silicate rock samples in terms of sensitivity, selectivity, operational simplicity and economy.     

2-Thion-5-mercapto-1,3,4-thiadiazolidin als Reagens für die photometrische Bestimmung von Platin(IV), Palladium(II) und Osmium(VIII)

A method for the photometric determination of platinum(IV), palladium(II) and osmium(VIII) with 5-mercapto-thiadiazolidine-thione-2 is described. The effects of an excess of reagent, of time, pH and of diverse ions were studied. The optimum concentration range for the method is 10 to 100 Μg of Pt(IV), Pd(II) and Os(VIII).     

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.