Spectrophotometric determination of palladium with 2-mercaptobenzoxazole

A new spectrophotometric method for the determination of palladium is described using 2-mercaptobenzoxazole as reagent. The color reaction has a sensitivity of 0.08 μg of Pd per cm² for log I₀/I = 0.001 and obeys Beer's law from 2 to 40 p.p.m. The effects of pH, time, order of addition of the reagents, temperature and diverse ions were investigated. The procedure was applied to synthetic solutions containing palladium plus a variety of foreign ions.     

Spectrophotometric determination of palladium with 2-mercaptomethyl-benzimidazole

Summary A spectrophotometric method has been developed for the determination of palladium with 2-mercaptomethyl-benzimidazole. This involves extraction of the palladium complex into iso-amyl alcohol in presence of 0.3 to 2N hydrochloric acid and 0.45 to 1.4M ammonium sulfate. The color is very stable and is highly selective for palladium. At 380 nm it obeys Berr's law in the concentration range of 1 to 9g of Pd per ml; the optimum range being 4 to 8g. The sensitivity and molar absorptivity of the reaction are 0.019g of palladium per cm² and 5600±70 respectively. The continuous variation and molar ratio methods indicate that palladium forms 12 complex with the ligand.

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Zusammenfassung Eine spektrophotometrische Methode zur Bestimmung von Palladium mit 2-Merkaptomethylbenzimidazol wurde ausgearbeitet. Der Palladiumkomplex wird mit Isoamylalkohol in Gegenwart von 0,3- bis 2-n Salzsäure und von 0,45- bis 1,4-m Ammoniumsulfat extrahiert. Die Farbe ist sehr beständig und sehr selektiv für Palladium. Bei 380 nm entspricht die Färbung dem Beerschen Gesetz zwischen 1 und 9g Pd/ml; der optimale Konzentrationsbereich liegt zwischen 4 und 8g. Die Empfindlichkeit der Reaktion beträgt 0,019g Pd/cm²und die molare Absorption 5600±70. Die Untersuchung nachJob ergab für den Komplex das Molverhältnis Pd: Reagens= 12.

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Résumé On a mis au point une méthode spectrophotométrique pour le dosage du palladium par le mercaptométhyl-2 benzimidazole. Elle met en jeu l'extraction du complexe du palladium par l'alcool isoamylique en présence d'acide chlorhydrique 0,3 à 2N et de sulfate d'ammonium 0,45 à 1,4M. La coloration est très stable et bien sélective pour le palladium. A 380 nm, elle suit la loi de Beer dans le domaine de concentration de 1 à 9g de Pd par ml; le meilleur domaine s'étend de 4 à 8g. La sensibilité et l'absorbance molaire de la réaction sont respectivement de 0,019g de palladium par cm² et 5600±70. Les méthodes des variations continues et du rapport molaire indiquent que le palladium forme un complexe 1,2 avec le coordinat.

     

Spectrophotometric determination of tungsten in ores and steel by chloroform extraction of the tungsten-thiocyanate-diantipyrylmethane complex

A method for determining up to about 6% of tungsten in ores and mill products is described. It is based on the extraction of the yellow tungsten(V)-thiocyanate-diantipyrylmethane ion-association complex into chloroform from a 2.4M sulphuric acid-7.8M hydrochloric acid medium containing ammonium hydrogen fluoride as masking agent for niobium. The molar absorptivity of the complex is 1510 1. mole(-1).mm(-1) at 404 nm, the wavelength of maximum absorption. Moderate amounts of molybdenum and selenium may be present in the sample solution without causing appreciable error in the result. Interference from large amounts is avoided by separating these elements from tungsten by chloroform extraction of their xanthate complexes. Large amounts of copper interfere during the extraction of tungsten because of the precipitation of cuprous thiocyanate. Common ions, including uranium, vanadium, cobalt, titanium, arsenic and tellurium, do not interfere. The proposed method is also applicable to steel.     

Spectrophotometric determination of palladium with sulfochlorophenolazorhodanine by flow injection

Sulfochlorophenolazorhodanine (as its sodium salt) has been used in the automated development of a sensitive flow-injection procedure for the spectrophotometric determination of palladium. The resulting method has high sample throughput, good precision, and low consumption of both sample and reagents. The optimum pH for the reaction is 5.0 and the response is constant at pH between 4.7 and 5.3. The sensitivity (calibration slope) of the procedure is 4.4 x 10(3) l./mole. The linear dynamic range is 0.045-30.0 mug/ml. The sample throughput is at least 120/hr. An automated procedure for optimization of analytical variables is described and a two-variable response surface for the system is given. Interference studies on 19 metal ions show that the method has good selectivity.     

Spectrophotometric determination of palladium with 2,2′-diquinolyl ketoxime

Summary A visible Spectrophotometric method is described for the determination of palladium with 2,2-diquinolyl ketoxime. The effects due to p_H, time, solvents, reagent concentration and diverse ions are reported. Beer's law is obeyed and the molar extinction coefficient is 1.3·10⁴ at 478 nm. The incorporation of EDTA into the procedure results in a highly specific method for the determination of trace amounts of palladium.

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Zusammenfassung Die spektralphotometrische Bestimmung von Palladium mit 2.2-Dichinolylketoxim wurde beschrieben. Über den Einfluß von p_H, Zeit, Lösungsmitteln, Reagenskonzentration und von diversen Fremdionen wurde berichtet. Das Beersche Gesetz ist erfüllt. Der molare Extinktionskoeffizient beträgt bei 478 nm 1.3·10⁴. Die Einführung von ÄDTA in das Verfahren führt zu einer hochspezifischen Bestimmung von Palladiumspuren.

     

Spectrophotometric determination of palladium after extraction of the chloro-stannous complex by tri-n-octylamine

The complex formed between palladium(II) and tin(II) in hydrochloric acid solutions, and its extractability by tri-n-octylamine were investigated. Two different species were obtained: one a brown-red complex and the other yellow. Both were extracted into tri-n-octylamine in benzene, but the yellow species which had a definite absorption maximum at 410 mμ was more suitable for the determination of palladium. A method is described for the spectrophotometric determination of palladium in the presence of many other elements. Both species are considered to be anionic and a mechanism for their extraction is proposed.     

Spectrophotometric determination of palladium using arsenazo I

A new simple rapid method for the spectrophotometric determination of palladium using arsenazo I is given. The optimum conditions favoring the formation of the complex are extensively investigated; the molecular structure was found to be 1:1. Beer's law is obeyed for the ranges 1.0–10.6 or 0.64–6.39 ppm of Pd.     

Spectrophotometric determination of traces of palladium after coprecipitation with tellurium

A spectrophotometric method for the determination of microgram amounts of palladium in the présence of much iron, copper, nickel, cobalt and other common elements (~ 0.5 g) is described. Palladium is separated by stannous chloride precipitation with tellurium as collector. p-Nitroso-diphenylamine is used as the colorimetric reagent, and diethyl oxalate as extradant for the palladium complex (sensitivity = 0.0015 μg $\text{Pd}\text{cm}{}^2$ ≡ log {I₀/I} = 0.001). Silver, selenium and tungsten lead to low results and should not exceed ~ 0.1 mg. The weight ratio Au/Pd should not exceed 10, else results for palladium are high. For Pd > 1 μg, recoveries average 90% or. better.     

Spectrophotometric determination of palladium with pyridine-2-aldehyde-2-quinolylhydrazone

A new, sensitive colorimetric procedure for the determination of microgram quantities of palladium(II) with pyridine-2-aldehyde-2-quinolylhydrazone is described. The reaction is practically instantaneous and not sensitive to variations in salt concentration. The platinum group metals do not interfere, and the analysis is possible with milligram amounts of these metals present.     

Spectrophotometric determination of palladium in titanium-base alloys, with dimethylglyoxime

A rapid spectrophotometric method for the determination of 0.1-1.0% of palladium in titanium alloys with dimethylglyoxime is described. The complex is extracted with chloroform and its absorbance measured at 380 nm. Beer's law is obeyed and the molar absorptivity is 170 l.mol(-1).mm(-1). None of the elements in common titanium alloys interfere. The method is rapid, simple and reproducible.     

Spectrophotometric determination of palladium(II) with 2-diethylaminoethanethiol hydrochloride and the simultaneous determination of rhodium and palladium

2-Diethylaminoethanethiol hydrochloride is proposed for spectrophotometric determination of palladium(II). The sensitivity of the reaction is 0.0085 smg/cm² and the yellow colored complex shows absorption maxima at 258 mμ and 303 mμ. Color development is slow in the cold but complete after heating for 10–15 min. The optimum pH range is 3.5 to 5.5 and the system adheres to Beer's law between 0.2 and 16.8 p.p.m. of palladium. The average and maximum relative standard deviations were 0.60% and 1.40% respectively. Interferences due to other platinum metals were studied and a procedure is suggested for the simultaneous determination of rhodium and palladium.     

Spectrophotometric determination of palladium as tetraphenylarsonium palladium(II) trichlorostannate

The optimum conditions for the formation of the complex, tetraphenylarsonium palladium(II) trichlorostannate, and its extraction into chloroform have been ascertained and a method has been developed for the spectrophotometric determination of microgram amounts of palladium in the presence of many other elements.     

Spectrophotometric determination of palladium with 5,6-dimethyl-1,3-indanedione-2-oxime

A rapid, sensitive and selective method has been developed for the determination of palladium with 5,6-dimethyl-1,3-indanedione-2-oxime in acetate buffer (pH 5.5). Beer's law is obeyed over the range 0.15-4.17 mug/ml palladium(II). The molar absorptivity at 370 nm is 2.98 x 10(4) 1.mole(-1).cm(-1). The method has been applied for the determination of palladium in synthetic mixtures corresponding to PtIr and Oakay alloys. An interesting feature of the system is the abnormal shape of the Job and molar-ratio plots obtained.     

Column chromatographic preconcentration of palladium with dimethyl glyoxime and acenaphthenequinone dioxime on naphthalene

A solid material consisting of dimethyl glyoxime (DMG), acenaphthenequinone dioxime (ANDO) or DMG-ANDO on naphthalene provides a very convenient, rapid and economical method for the preconcentration of palladium in synthetic samples. Pd-DMG, Pd-ANDO and Pd-DMG-ANDO are quantitatively retained on naphthalene in the column in the pH ranges 2.2–4.4, 1.8–5.6 and 1.7–6.8, respectively. The solid mixture consisting of the metal complex together with naphthalene is stripped from the column with 5 ml of dimethylformamide (DMF)-n-butylamine and the absorbance is measured at 247.6 nm with an atomic absorption spectrometer. Calibration graphs are linear over the palladium concentration range 5–25 μg per 5 ml of the final solution for all the three complexes. Ten replicate determinations of a sample solution containing 10 μg of palladium gave mean absorbances of 0.180, 0.225 and 0.230 with relative standard deviations of 1.8, 1.7 and 1.6% using the reagents DMg, ANDO and DMG-ANDO, respectively. The sensitivity of the method is better than the direct atomic absorption spectrometric determination of palladium. It is highest in case of the mixed ligands, i.e., DMG-ANDO (0.038 μg ml^?1 for 1% absorption). The method can be applied to the trace determination of palladium in complex materials.     

Liquid-liquid extraction and spectrophotometric determination of palladium with 2-mercaptobenz-amide

2-Mercaptobenzamide (MBA) was investigated as a reagent for the extraction of palladium. The palladium complex of MBA was extracted into tributyl phosphate (TBP). The pK_a of the ligand was 5.45 with the stability constant of the palladium complex β₂=10^7.1. The composition of the complex in TBP was Pd:MBA:TBP=1:2:2. Addition of sodium chloride accelerated the rate of extraction. Various interfering ions could be masked with EDTA; Ag(I), Au(III), Os(VIII), Se(IV), Te(IV) etc. interfered. The molar absorptivity was 1.59×10⁴ l mol^?1 cm^?1; 1–35 μg Pd could be determined at pH 6.0.     

1-（2′-苯并噻唑）-3-（4′-羧基苯）三氮烯固相萃取分光光度法测定钯

根据新试剂1-(2′-苯并噻唑)-3-(4′-羧基苯)三氮烯(BTCBT)与钯的显色反应及C8固相萃取小柱对显色络合物的固相萃取,建立了一种测定痕量钯的新方法,在pH为5.0~6.3的柠檬酸氢二钠-NaOH缓冲介质中,在乳化剂OP和SDBS存在下,钯与BTCBT发生反应形成1∶2的稳定络合物,该络合物可用C8固相萃取小柱富集,小柱上富集的络合物用乙醇洗脱后用分光光度法测定,在富集后的测定液中,络合物最大吸收波长为490 nm,摩尔吸光系数ε=1.16×105L.mol-1.cm-1,Pd2 量在0.1~1.2μg/mL内符合比尔定律,方法适用于测定催化剂中的钯。