Amperometric determination of palladium with 2-(o-Hydroxyphenyl) Benzoxazole

Summary A method for the amperometric determination of palladium is presented, which involves the formation of a palladium-2-(o-hydroxyphenyl) benzoxazole inter complex salt. The method is primarily recommended for the accurate determination of palladium in solutions containing only traces of other platinum elements. Of the several diverse ions studied, only iridium interfered seriously with the determination of palladium; however, this element is easily removed from palladium according to the standard procedure². The data obtained in the amperometric investigation of the palladium-2-(o-hydroxyphenyl) benzoxazole interaction were in agreement with the results obtained in the gravimetric study of the same reaction⁷.     

Gravimetric determination of palladium with biguanide sulfate

Biguanides are interesting reagents for the determination of palladium owing to their solubility, chemical resistance, and selectivity in moderately acidic solutions. A procedure for the gravimetric determination of palladium(II) in the form of Pd(HL)₂SO₄, where HL = biguanide, is proposed and the conditions of precipitation, treatment of the precipitate, precision, accuracy, and selectivity of the procedure are discussed.     

Gravimetric determination and radiochemical separation of palladium(II) with ethyl-α-isonitrosoacetoacetate

The use of ethyl-ga-isonitrosoacetoacetate (HEINA) for determination of palladium is reported. Pd can be estimated quantitatively from 0.5M to 2M HCl solution. Accurate results are obtained in 1M solution with an accuracy better than 1%. Decontamination values against platinum metals and other metals usually associated with Pd are greater than 10⁵. The time required for gravimetric determination is about an hour, for radiochemical separation about 25 min and the recovery is better than 90%.     

Gravimetric and spectrophotometric determination of palladium with 2-hydroxy-5-methylpropiophenone oxime

2-hydroxy-5-methylpropiophenone oxime (HMP) reacts with palladium in strongly acidic media to form a yellow water-insoluble complex. Palladium has been determined gravimetrically and interference by certain ions studied. The yellow complex is extractable into carbon tetrachloride in the pH range 1-4. The absorption maximum of the complex lies at 375 mmu, and Beer's law is obeyed in the range 0-15 ppm of palladium. The sensitivity is 0.22 mug Pd/cm(2) for log I(0)/I = 0.001. The effect of a number of foreign ions has been studied and several can be tolerated to an appreciable extent. The ratio of metal: ligand in the complex is 1:2.     

Gravimetric determination of palladium with quinolinimide as a reagent

Summary Quinolinimide which is found to be a selective reagent for palladium forms a complex of the composition Pd(C₇H₃O₂N₂)₂. The reagent quantitatively precipitates palladium from solutions of p_H 0.5 to 2.5 in presence of common ions as well as platinium metals, except tin which, however, can be kept in solution by complexing with citric acid. The palladium complex being stable up to 307° C can be directly weighed.

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Zusammenfassung Chinolinimid wird als selektives Reagens für Palladium vorgeschlagen. Bei p_H-Werten zwischen 0,5 und 2,5 kann Palladium quantitativ in Form des Komplexes Pd(C₇H₃O₂N₂)₂ gefällt werden, wobei die meisten anderen Ionen, auch die der Platinmetalle, in Lösung bleiben. Zinn stört, kann aber mit Citronensäure maskiert werden. Der Palladiumkomplex ist bis 307° C stabil und kann direkt ausgewogen werden.

     

Spectrophotometric determination of palladium with 4-(2-pyridylazo)resorcinol

Summary A simple photometric method for the determination of palladium has been worked out, employing pyridylazo-resorcinol (PAR) as a complexing ligand for the metal ion. The coloured species is extractable into chloroform in the presence of diethylamine, the absorbance of which is measured at 535 nm. The method is free from the interference of a large number of elements particularly the other platinum metals. It obeys Beer's law in the range of 0–3 g Pd/ml with Sandell's sensitivity of 0.0034 g Pd cm^–2. The ratio of metal to ligand in the complex is found to be 1:1. Analysis of various samples has been carried out with satisfactory and reproducible results (standard deviation ±0.002).     

Spectrofluorimetric determination of cysteine by 5-maleimidyl-2-(m-methylphenyl)benzoxazole

A new thiol weak-fluorescence probe, 5-maleimidyl-2-(m-methylphenyl)benzoxazole (MMPB), gives a highly fluorescence product in the presence of Cys. In this paper, MMPB has been developed for the fluorimetric determination of cysteine (Cys). At lambda(ex)/lambda(em) = 305.6/425.6 nm, the linear range is from 0 to 3.3 x 10(-7) mol l(-1) and the detection limit (sigma = 3) of 6.2 x 10(-10) mol l(-1). The main advantage of this method lies in the relative high selectivity compared with the methods using other N-substituted maleimide type of thiol reagents, in which 0.15-fold (molar ratio) of GSH is allowed and most of other amino acids at 100-fold (molar ratio) level had no obvious effect on the results. The proposed method has been applied to the determination of Cys in real samples.     

Efficient synthesis of 2-(2′-hydroxyphenyl)benzoxazole by palladium(II)-catalyzed oxidative cyclization

An efficient method for the synthesis of 2-(2′-hydroxyphenyl)benzoxazole has been developed by using palladium-mediated oxidative cyclization.     

Spectrophotometric determination of palladium with 4-(2-pyridylazo)-resorcinol (PAR)

Summary A spectrophotometric method for the determination of palladium is described using 4-(2-pyridylazo)-resorcinol as reagent. The method involves the formation of two red coloured chelates of palladium-PAR at p_H 4.0 and 10.5 respectively. The colour reactions have sensitivity of 0.0085g cm^–2 and 0.0071g cm^–2 for logI ₀/I= 0.001. The effects of p_H, time, order of addition of reagents, temperature etc. have been investigated. The composition of the complexes (metalreagent) have been confirmed by two methods as 11 (at p_H 4.0) and 32 (at p_H 10.5).

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Zusammenfassung Eine spektrophotometrische Methode zur Palladiumbestimmung mit PAR [4-(2-Pyridylazo)-resorcin] wurde beschrieben. Zwei rotgefärbte Chelate werden bei p_H 4,0 bzw. 10,5 gebildet. Die Empfindlichkeit der beiden Reaktionen beträgt 0,0085 bzw. 0,0071g · cm^–2. Der Einfluß von p_H, Zeit, Reihenfolge der Reagenzien, Temperatur usw. wurde untersucht. Die Zusammensetzung der Komplexe entspricht dem Molverhältnis Pd: Reagens= =11 bei p_H 4,0 bzw. 32 bei p_H 10,5.

     

Gravimetric, volumetric and conductometric determination of palladium with pyridine

Summary Palladium has been determined gravimetrically as palladium pyridine iodide complex, volumetrically as palladium pyridine iodide and palladium pyridine thiocyanate complex and conductometrically as palladium pyridine iodide, thiocyanate, azide and dichromate. Advantages of the different methods and interferences of various ions have been discussed in each case. Determination is possible in the presence of Pt, Rh, Ru, Ir and Os.

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Gravimetrische, volumetrische und konduktometrische Bestimmung von Palladium mit Pyridin

Zusammenfassung Die Bestimmung wird gravimetrisch als Pd-Pyridin-Jodid-Komplex, volumetrisch als Pd-Pyridin-Jodid sowie -Thiocyanat-Komplex und konduktometrisch als Komplex von Pd und Pyridin mit Jodid, Thiocyanat, Azid oder Dichromat durchgeführt. Vorteile und Störungen der einzelnen Methoden werden diskutiert. Die Bestimmungen können in Gegenwart von Pt, Rh, Ru, Ir und Os vorgenommen werden.

     

Gravimetric and spectrophotometric determination of palladium with 2,3,4-pentanetrione trioxime

A study of the use of 2,3,4-pentanetrione trioxime (PTT) in the gravimetric and spectrotrophotometric determination of palladium is reported. PTT has been applied to the determination of palladium in various synthetic and standard samples. The reagent has some advantages over dimethylglyoxime.     

Gravimetric determination of uranium(vi) with n-benzoylphenylhydroxylamine

Uranium(VI) can be quantitatively precipitated by N-benzoylphenylhydroxylamine at pH 5.4. The precipitate is weighed after ignition to U₃O₈, or directly as U0₂(C₁₃H₁₀O₂N)₂. Cerium(III). thorium, lead and bismuth can be masked with magnesium-EDTA complex. Iron(IlI), titanium (IV) zirconium and molybdenum(Vl) and small amounts of aluminium can be precipitated with the reagent and filtered before uranium(Vl) is determined in the filtrate by proper adjustment of acidity. Fluoride, carbonate and organic acids interfere.     

Gravimetric determination of tungsten(vi) with n-benzoyl-n-phenylhydroxylamine

Tungsten can be quantitatively precipitated with N-benzoylphenyl-N-hydroxylamine in presence of hydrochloric acid (0.5–1 N). The precipitate can be weighted as WO₂(C₁₃H₁₀O₂N)₂ or WO₃. Molybdenum, vanadium, titanium, and iron can be separated by prior precipitation of these mutais with the above reagent in presence of tartrate ions; tungsten is then determined in tlie filtrate. L'ranium does not interfere, but chromium (VI), fluoride and phosphate do.     

Rapid spectrophotometric determination of palladium in titanium alloys with 2-(5-bromo-2-pyridylazo)-5-(diethylamino)phenol

A rapid spectrophotometric method for the determination of Pd in titanium alloys is proposed. It is based on the reaction of 2-(5-bromo-2-pyridylazo)-5-(diethylamino)phenol with Pd(II) in a sulphuric acid medium in the presence of ethanol. Beer's law is obeyed up to 40 mug of Pd. The molar absorptivity is 4.5 x 10(4) 1.mole(-1).cm(-1). The standard deviation is 0.3 mug of Pd and the coefficient of variation varies from 0.8 to 3.3%. The elements ordinarily present in such alloys do not interfere. High selectivity is achieved by using fluoroboric acid as masking agent. Improvements in the method of sample decomposition also contribute to the rapidity of the method.     

Gravimetric determination of copper(II) with p-aminobenzoic acid

A method has been developed for the gravimetric determination of 20-100 mg of copper(II) with p-aminobenzoic acid. Ag, Hg(II), Pb, Al, Fe(II), Bi, Sb(III) and Sn(II) interfere, but Zn, Co(II), Ni and Cd do not. The precipitate can be weighed after drying at 80-100 degrees , or can be ignited to copper(II) oxide at temperatures above 400 degrees , and weighed in this form.