Rapid spectrophotometric determination of platinum with trifluoperazine dihydrochloride

Trifluoperazine dihydrochloride reacts with platinum(IV) in sodium acetate-hydrochloric acid buffer containing copper(II) catalyst to form a bluish-green 1:1 complex with absorbance maximum at 504 nm. A 50-fold ratio of reagent to metal ion is necessary for complete complexation. Beer's law is valid over the concentration range 0.5-8 ppm of platinum(IV) with optimum concentration range 1-7 ppm. The molar absorptivity is 6.50 x 10(3) l.mole(-1).cm(-1). The effects of pH, time, temperature, concentration of reagent and copper, order of addition of reagents, and the interferences from various ions are reported.     

Spectrophotometric determination of microgram amounts of platinum

2-Ethyl-10-[3-(dimethylamino-2-methyl)propyl]phenothiazine hydrochloride (ethylisobutrazine hydrochloride) forms an orange-red complex with platinum(IV) at room temperature (26 ± 2 °C) in hydrochloric acid-sodium acetate buffer medium containing copper(II) ions. The complexation is complete within 10 min. The complex exhibits an absorption maximum at 529 nm with a molar absorptivity of 1.90 × 10⁴ liters mol^?1 cm^?1. Beer's law is obeyed over the concentration range 0.4–7.8 ppm of platinum. A 50-fold molar excess of the chromogenic reagent is necessary for the development of maximum color intensity. Job's method of continuous variation, the molar-ratio method, and the slope-ratio method indicate a 1:1 composition for the complex. The effects of pH, time, temperature, reagent concentration, order of addition of reagents, and interference of various ions are reported. The reagent has also been used successfully for the determination of platinum in minerals and alloys.     

Spectrophotometric determination of ruthenium with 3,4-diaminobenzoic acid

Ruthenium(III) chloride and 3,4-diaminobenzoic acid, in aqueous solution at pH 4.0-4.5, react slowly at room temperature, but more rapidly when the mixture is heated, giving solutions that go through colour transitions from amber to purple-red; maximum absorbance of fully developed solutions occurs at 550 nm. The effects of heating temperature and time, pH, reagent concentration, and other variables have been studied. The system conforms to Beer's law; optimum concentration range, for measurement in 10-mm cells, is about 0.5-2 ppm of ruthenium. Interference from foreign ions, especially other platinum elements, is avoided by a distillation separation of ruthenium. The spectrophotometric mole-ratio and continuous-variation methods indicated the presence of complexes of 1:2 and 1:3 ruthenium-to-reagent stoichiometry. Elemental analysis of solid products isolated from solution confirmed the 1:2 reaction ratio. Several other o-diamines gave similar coloured solutions and reaction stoichiometry.     

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.     

Absorptiometric determination of palladium with 2,3-quinoxalinedithiol

A method is described for the absorptiometric determination of palladium, in the range 0.1-2.5 ppm, with 2,3-quinoxalinedithiol (H(2)qdt) in aqueous ethanol. The reagent, S-2-(3-mercaptoquinoxalinyl) thiuronium chloride (mgt), is hydrotysed rapidly to (qdt)(2-) at pH 10. In the presence of zinc, (qdt)(2-) is stabilized by complex formation and reagent blanks are reduced almost to zero. An anionic 1:2 complex of palladium(II) and (qdt)(-2) is formed at pH 10, having maximum absorbance at 454 nm and Sandell sensitivity index of 0.0032 mug cm (2). The reaction is moderately selective; equivalent concentrations of platinum(IV), iridiuin(IV) and rhodium(III) can be tolerated but gold(III), copper(II) and a few other metals interfere. Suggestions are made for masking interferences. The method is characterized by good precision, with a relative standard deviation of 0.25% at the 1-ppm level.     

Disulphides of dithiophosphinic acids as analytical reagents-I Extractive spectrophotometric determination of palladium with some bis(dialkylthiophosphoryl)- and bis(diarylthiophosphoryl)disulphides

The disulphides of dithiophosphinic acids (DS) with the general formula R(2)P(S)SSP(S)R(2), where R = C(2)H(5), C(3)H(7), C(5)H(11), C(6)H(5) (I-IV) form coloured complexes of 1:3 stoichiometry with Pd(II). The absorption maxima and molar absorptivities are: a lambda(I) = 302 nm, epsilon(I) = 2.04 x 10(4) 1.mole(-1).cm(-1); lambda(II) = 305 nm, epsilon(II) = 2.58 x 10(4); lambda(III) = 303 nm, epsilon(III) = 2.60 x 10(4); lambda(IV) = 315 nm, epsilon(IV) = 3.25 x 10(4). The reaction takes about 3 min at room temperature, and the colour is stable for 24 hr. The influence of time, pH, reagent concentration, organic solvents and interferences have been studied. An extractive photometric method of determination of Pd(II) is described and applied to the determination of Pd(II) in a mixture of platinum metals.     

Spectrophotometric determination of osmium with 2R-acid in the presence of other platinum metals

Osmium(VIII) produces two coloured species with lambda(max) 680 nm (green) and 530 nm (red) with excess of 2-amino-8-naphthol-3,6-disulphonic acid in aqueous solution. The green complex is stable between pH 2.5 and 8.0 and the red complex between pH 11.0 and 12.0. The effects of temperature and time, reagent concentration, optimum conditions for the spectrophotometric determination of trace amounts of osmium, and other variables, have been studied at pH 11.5. At this pH, other platinum metals do not interfere. The sensitivity of the colour reaction is 0.2 microg/cm(2) and the system conforms to Beer's law over a concentration range of 1.5-10 microg of osmium.     

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).     

Spectrophotometric studies on platinum—Promethazine hydrochloride complex

Promethazine hydrochloride forms a yellowish-green complex with platinum(IV) in sodium acetate-hydrochloric acid buffer containing copper catalyst. The complex has an absorption maximum at 406 nm with molar absorptivity 1.001 × 10⁴ liters mol^?1 cm^?1. The sensitivity of the reaction is 19.5 ng/cm² for $\text{log}\text{I °}\text{I}\text{= 0.001}$. Beer's law is valid over the range 0.5–7.5 ppm of platinum(IV) with optimum concentration range 0.8-7.3 ppm. Continuous variations, mole ratio, and slope ratio methods indicate 1:1 composition for the complex. The effects of pH, time, temperature, order of addition of reagents, reagent concentration, and interferences from various ions are reported.     

A highly sensitive spectrophotometric determination of platinum(IV) using leuco xylene cyanol FF

A new, simple, highly sensitive and rapid spectrophotometric method has been described for the determination of platinum(IV). The method is based on the oxidation of leuco xylene cyanol FF (LXCFF) to its blue form of xylene cyanol FF by platinum(IV) in sulfuric acid medium (pH 1.0-2.5), the formed dye shows an absorption maximum at 620 nm in acetate buffer medium (pH 3.0-4.5). The method obeys Beer's law over a concentration range of 0.3 to 2.6 micro g mL(-1) platinum, having molar absorptivity and Sandell's sensitivity of 5.1x10(4) L mol(-)(1) cm(-1) and 0.0038 micro g cm(-2), respectively. The optimum reaction conditions and other analytical parameters have been evaluated. The developed method has been successfully applied to the determination of platinum in pharmaceutical preparations, soil, natural water, plant material, platinum-containing catalyst, and synthetic alloy samples.     

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.     

2,2'-Diaminodiphenyldisulphide-a new sensitive spectrophotometric reagent for platinum

2,2'-Diaminodiphenyldisulphide is a highly sensitive platinum chromogen. Platinum(IV) forms a complex with it in 50% aqueous ethanol at pH 5.0-6.0, having maximum absorption at 725 nm. The molar absorptivity of the complex is 5.48 x 10(4)1.mole(-1).cm(-1) at 725nm and the sensitivity is 0.0035 mug/cm(2). The colour system obeys Beer's law from 0.25 to 5 ppm with optimum concentration range 0.75-4 ppm of platinum. The relative error is 2.7%. The metal to reagent ratio is 1:2, and the stepwise formation constants K(1) and K(2) are 5.6 x 10(4) and 1.96 x 10(4) respectively.     

Development of novel reagent for Hantzsch reaction for the determination of formaldehyde by spectrophotometry and fluorometry.

A novel reagent, acetoacetanilide (AAA), was introduced to the determination of formaldehyde based on Hantzsch reaction. A simple and highly sensitive fluorometric method was achieved by using AAA. The main advantages in the use of this reagent are: the reaction is carried out at room temperature without any heating system, the cyclization product based on Hantzsch reaction is soluble in water, and the product can be detected by spectrophotometry and fluorometry. The maximum absorption wavelength of the product occurs at 368 nm, and the maximum excitation and emission wavelengths are found at 370 and 470 nm, respectively. Several important experimental variables of the procedures were examined; particularly, the reaction temperature, reaction time, concentrations of reagents, and pH of the reagent solution were optimized for improving the detecting sensitivity. The calibration graph was linear in the range of 1 x 10(-7) - 1 x 10(-6) M or much higher concentrations. The limit of detection (LOD), based on three times of the standard deviation of the reagent blank, was 2.0 x 10(-8) M. The proposed method was applied to the determination of formaldehyde in environmental water samples. Many foreign species commonly existing in water samples did not interfere with the determination of formaldehyde in the proposed method.     

Extraction of gold(III), palladium(II), and platinum(IV) by 1-[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-ylmethyl]-1<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazole from hydrochloric acid solutions

The extraction of gold(III), palladium(II), and platinum(IV) with 1-[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl]-1H-1,2,4-triazole from hydrochloric acid solutions into toluene has been studied. The extraction follows the anion-exchange mechanism. The concentration constants and thermodynamic parameters of the extraction reaction have been calculated. The reagent is proposed for use in the extraction of the sum of precious metals.     

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.     

Fluorimetric determination of peroxynitrite based on an enzymatic reaction.

A novel fluorimetric method for the determination of peroxynitrite (ONOO-) using hemoglobin (Hb) as a catalyst is described. The method employs the reaction of ONOO with thiamine (TM), a colorless, non-fluorescent reagent in a glycine-NaCl-NaOH buffer solution (pH 12.7), to generate a highly fluorescent product, thiochrome (TC). The fluorescent product was monitored by fluorimetry. A linear calibration graph was obtained over an ONOO- concentration range from 4.95 x 10(-7) mol L(-1) to 2.97 x 10(-5) mol L(-1), with a detection limit of 9.78 x 10(-9) mol L(-1) ONOO-. The relative standard deviation at an ONOO- concentration of 2.11 x 10(-6) mol L(-1) was 4.15% (n = 9).     

Spectrophotometric determination of some drugs for osteoporosis

Three simple, accurate and sensitive spectrophotometric methods are developed for the determination of some new drugs for the treatment of osteoporosis: risedronate sodium (I), alendronate sodium (II) and etidronate disodium (III). The first method is based on the measurement of difference in absorbance (Delta A) of risedronate sodium in 0.01 mol l(-1) hydrochloric and 0.1 mol l(-1) sodium hydroxide at 262 nm. Beer's law is obeyed over a concentration range of 15-150 microg ml(-1) with mean recovery 99.75+/-1.22 and molar absorptivity (epsilon) 1.891 x 10(3). The second method is based on the reaction of the primary amino group of (II) with ninhydrin reagent in methanolic medium in the presence of 0.05 mol l(-1) sodium bicarbonate. The colored product is measured at 568 nm, and the linearity range is found to be 3.75-45 microg ml(-1) with mean recovery 99.77+/-0.73 and epsilon 9.425 x 10(3). The third method is based on oxidation of the three mentioned drugs with ceric (IV) sulphate in 0.5 mol l(-1) sulphuric acid at room temperature and subsequent measurement of the excess unreacted cerium (IV) sulphate at 320 nm. The method obeyed Beer's law over a concentration range of 2-24 microg ml(-1) for the three drugs with mean recovery 99.79+/-1.16, 99.73+/-1.38 and 99.86+/-1.13 and epsilon 14.427 x 10(3), 13.813 x 10(3) and 14.000 x 10(3) for drugs I, II, III respectively. The proposed methods were successfully applied for the determination of the studied drugs in bulk powder and in pharmaceutical formulations. The results were found to agree statistically with those obtained the reported methods. Furthermore, the methods were validated according to USP regulations and also assessed by applying the standard addition technique.     

Studies on 2-(2-thiazolylazo)-5-diethylaminophenol as a precolumn derivatizing reagent in the separation of platinum group metals by high performance liquid chromatography

Five platinum group metals, Pt(II), Ir(IV), Ru(III), Rh(III) and Os(IV) have been separated by high performance liquid chromatography (HPLC) using 2-(2-thiazolylazo)-5-diethylaminophenol (TADAP) as a precolumn derivatizing reagent. The whole analysis was completed on a C(18) column in 23 min at 574 nm, with the mobile phase of methanol-water (69.5:30.5, v:v) containing 4 mmol l(-1) tetrabutylammonium bromide (TBA Br) and 10 mmol l(-1) pH6.0 acetate buffer. The detection limits (S/N=3) of Pt(II), Ir(IV), Ru(III), Rh(III) and Os(IV) were 0.39, 9.74, 1.64, 0.29 and 1.29 ng ml(-1), respectively. This method was rapid, sensitive and simple.     

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.     

Measurements of carbon dioxide with the air-gap electrode. Determination of the total inorganic and the total organic carbon contents in waters.

Ruthenium(II) reacts with 3-(2-pyridyl)-5.6-diphenyl-1,2.4-triazine (PDT) in water-alcohol solution at pH 5 to give a magenta-colored cationic complex having an absorption peak at 485 nm. The color is fully developed by heating at 85° C for 30 min. The system conforms to Beer's law; the optimal concentration range for measurement at 1.00-cm optical path is about 0.5–3.4 p.p.m. of ruthenium. The molar absorptivity is 2.1 · 10⁴ 1 mole^-1 cm^-1. The effects of reagent concentration, heating temperature and time, pH, and alcohol concentration have been studied. Common anions do not interfere. Separation from interfering cations is effected by distillation and recovery of ruthenium tetroxide. Spectrophotometric methods of continuous variations and of mole ratios, and elemental analysis of solid salts isolated from solution, indicate a ruthenium-to-PDT stoichiometry of 1:2, the PDT acting as a tridentate ligand.