Determination of traces of palladium using radioactive zinc dithizonate as a reagent

A radioreagent method for the analysis of traces of palladium using radioactive zinc dithizonate as the reagent has been developed. The method is rapid, highly selective and palladium concentration down to 2 g present in 10 ml solution can be measured.     

H-Point Standard Addition Method for Simultaneous Determination of Palladium and Cobalt

The H-point standard addition method (HPSAM) has been applied to simultaneous determination of palladium and cobalt at trace levels, using 1-(2-pyridylazo)-2-naphthol (PAN) as a chromogenic reagent. Palladium and cobalt at neutral pH levels form green colored neutral complexes with PAN which are soluble in aqueous sodium dodecylsulfate (SDS) micellar media and can be monitored spectrophotometrically. Simultaneous determination of cobalt and palladium by HPSAM were performed spectrophotometrically and under optimum conditions. Absorbances at the two pairs of wavelengths, 597 and 650 nm or 566 and 612nm, were monitored while adding standard solutions of cobalt or palladium, respectively. The method is able to accurately determine a cobalt/palladium ratio of between 5:1 and 1:30 (wt/wt). The accuracy and reproducibility of the determination method for various known amounts of cobalt and palladium in their binary mixtures were evaluated. The effects of diverse ions on the determination of cobalt and palladium to investigate the selectivity of the method were also studied. The recommended procedure was applied to real water samples and synthetic sample solutions.     

Comparative study of magnesium nitrate,palladium nitrate and reduced palladium for the direct determination of mercury in sea water by electrothermal atomization atomic absorption spectrometry

A comparative study of different chemical modifiers in graphite furnace atomic absorption spectrometry for the direct determination of mercury in sea water samples, in synthetic sea water sample of high (72.8%) and low 34.2%) salinity and in aqueous solutions, was carried out. The use of reduced palladium produces better results. The mixture of palladium nitrate and ascorbic acid, gives the best limit of detection (1.9 gl^–1). The use of reduced palladium and magnesium nitrate produced excellent recoveries (close to 100%) in the whole salinity range for all mercury concentration tested. The use of palladium nitrate alone or combined with magnesium nitrate gave good recoveries with respect to a real sea water sample for low salinities. The interference from the major components of sea water were completely removed by using reduced palladium and magnesium nitrate modifiers. Thus, a single calibration curve with synthetic sea water may be applied to the analysis of sea water samples of widely differing salinities.     

Behaviour of chromium in the graphite furnace during the performance of the flameless absorption spectrometry

Summary An automated continuous monitoring method for total mercury at sub-ppb level based on cold vapor atomic-absorption-continuous micro flow analysis is developed. The method uses continuous micro flow sample partial digestion, reduction and extraction in small bore tubes at low flow rates of reagents. Tin(II) chloride in sodium hydroxide solution was used as a reducing reagent. A mixed solution of potassium peroxodisulphate and copper(II) ion was used as oxidizing and catalytic reagent, respectively. The method was successfully applied to the completely continuous monitoring of total mercury in both wastewater and saline water without a heating digestion bath.

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Kontinuierliche Mikromethode zur Durchflußüberwachung von Gesamtquecksilber im Sub-ppb-Bereich in Abwasser und anderen Wässern mit Hilfe der Kaltdampf-AAS

     

Screening of Fish Tissue for Methyl Mercury Using the Enzyme Invertase in a Solvent Interface

This paper describes a simple and rapid screening system for the extraction and determination of methyl mercury in tissue samples from fish. A novel clean-up procedure based on the use of two immiscible phases, an organic one containing methyl mercury and an aqueous one containing invertase, was developed. Methyl mercury was selectively extracted from the organic into the aqueous phase by its irreversible reaction with thiol groups of invertase, and the resulting inhibition of enzymatic activity served as a measure of methyl mercury concentration. Enzyme activity was measured with a spectrophotometric method using 3,5-dinitrosalicylic acid as a reagent. After parameter optimisation including pH, substrate concentration, and enzyme reaction time, it was possible to determine methyl mercury in the ppb range with this technique. Concentrations as low as 10ppb of methyl mercury in the extract, corresponding to 0.2ppm of methyl mercury in fish, were detected. The proposed procedure was successfully demonstrated as a simple screening method for methyl mercury in fish samples.     

Indirect complexometric determination of palladium(II) using sodium nitrite as a selective masking reagent

A selective complexometric method is described for the determination of palladium, sodium nitrite being used as masking reagent. Palladium(II) in a given sample solution is initially cornplexed with an excess of EDTA and the surplus EDTA is titrated with zinc sulfate solution at pH 4.5–5.5 (acetic acid-sodium acetate buffer), using xylenol orange as indicator. An excess of sodium nitrite is then added, the mixture is shaken well and the EDTA released from the Pd-EDTA complex is titrated with a standard zinc sulfate solution. Results are obtained for 2.5–27.5 mg of Pd with relative errors 0.5% and standard deviations 0.05 mg. The interferences of various ions are studied. The method is applied for the determination of palladium(II) in alloys and complexes.     

Spectrophotometric determination of trace mercury(II) in cereals with 2,4-bis(4-phenylazophenylaminodiazo)benzenesulfonic acid

A simple and low cost method for the determination of mercury has been developed. The method was based upon the highly sensitive color reaction of mercury(II) ions with 2,4-bis(4-phenylazophenylaminodiazo)benzenesulfonic acid (BPPABSA). We found that in the presence of 2.0% Triton X-100, the reagent reacts with mercury to form a stable red complex in a borax buffer solution at pH 10.22. The formed complex shows an absorption maximum at 530 nm. The apparent molar absorptivity is 2.18 × 10⁵ L/mol cm. The content of mercury in the sample was low and some foreign ions might interfere with the determination of mercury(II), so we used sulfhydryl dextran gel (SDG) to separate and enrich trace mercury(II), which lead to a satisfactory result. Under the optimal conditions, Beer’s law is obeyed in the range of 0–15 μg/25 mL Hg²⁺, the detection limit and relative standard deviation are 0.86 ng/mL and 1.4–3.8%, respectively. The method has been applied to the determination of mercury in cereals with satisfactory results.     

Seperations involving sulphides : Separation of alkaline earth metals from some elements that form sulphides

It has been shown that 2N sodium sulphide reagent can be used efficiently for separating. 1.Barium from rhenium, platinum, gold, bismuth, palladium, lead or cadmium. 2.Strontium, calcium and magnesium from rhenium, platium, gold, mercury, bismuth, palladium, lead or cadmium     

Simple oxidative pretreatment for determination of organomercury by cold vapour atomic fluorescence spectrometry

A simple and rapid method has been developed for the direct determination of organomercury in toluene extracts. The oxidative pretreatment, intended for cold vapour-atomic absorption/fluorescence spectrometry, involves the use of bromide/bromate reagent under strong acid conditions. The pretreatment is performed directly in a volumetric flask and avoids the need for back extraction and phase separation. Recoveries for methyl mercury additions to toluene, at the 2 g/1 level, ranged from 100–106%.On leave Xianjiang Environmental Research Institute, Urumqui, Xianjiang Province, Peoples Republic of China     

Simultaneous determination of copper,mercury and lead by first-order derivative spectrophotometry using dithizone as reagent

A first-order derivative spectrophotometric method has been developed for the simultaneous determination of copper, mercury and lead at g/L levels using dithizone as reagent. The procedure involves the simultaneous extraction of these elements by dithizone in chloroform from weakly alkaline solutions. Linear calibration curves were obtained in the ranges 0.5–10 (Cu), 1–10 (Hg) and 1–10 (Pb) g present in 40 ml of aqueous phase with detection limits of 5 g/L (Cu) and 20 g/L (Hg and Pb). The R.S.D.s for 100 g/L of copper, mercury and lead were 2.5, 2.6 and 3.1% respectively, for 5 determinations. The method is applicable for the determination of copper and lead in marine sediment samples with good precision and accuracy.     

Réaction spécifique pour le Palladium et son dosage

Résumé Parmi les dihydrazides des acides dicarboxyliques, le plus intéressant est celui de l'acide malonique qui fournit un réactif qualitatif spécifique du palladium. Le dosage gravimétrique ne s'applique pas, mais la colorimétrie permet d'évaluer de 2 à 10g/ml de palladium, à 285 nm.

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Specific reaction for palladium and its determination

Summary The most interesting of the dihydrazides of dicarboxylic acids is that of malonic acid, which yields a qualitative specific reagent for palladium. The gravimetric determination is not practicable but the colorimetric method permits the evaluation of from 2 to 10g/ml of palladium at 285 nm.

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Zusammenfassung Unter den Dicarbonsäure-Dihydraziden ist das interessanteste das der Malonsäure. Es ist ein für Palladium spezifisches Nachweisreagens. Zur gravimetrischen Bestimmung eignet es sich nicht, aber kolorimetrisch kann man bei 285 nm 2 bis 10g Pd/ml bestimmen.

     

2-Mercaptobenzimidazole (2-benzimidazolethiol) as a colorimetric reagent for palladium

Summary A spectrophotometric method for the determination of palladium using 2-mercaptobenzimidazole is described. The orange-yellow colour developed in aqueous medium atph 1.0–2.6 by the addition of an alcoholic solution of the reagent, is measured at 380 m. The system is found to obey Beer's law. The interference limits of diverse ions are also given.     

Optical and Chromaticity Characteristics of Cobalt and Palladium 4-(2-Pyridylazo)resorcinates

Optical and chromaticity characteristics (diffuse reflectances, chromaticity coordinates, lightness, color saturation, yellowness, color tint, and whiteness) of cobalt and palladium complexes of 4-(2-pyridylazo)resorcinol were determined at pH 7.2–7.9 and in 1 M H₂SO₄. The conditions of the separate determination of cobalt and palladium in the presence of each other by changing the order of the addition of reagent and using bifunctional chromaticity measurements and two-wavelength spectrophotometry are specified. The advantages of the chromaticity measurements are demonstrated. The proposed procedures were used for the analysis of model mixtures, binary cobalt–palladium alloys, and cobalt and palladium catalysts.     

Electroreduction Kinetics of Palladium(II) Complexes with α-Alanine: A Polarographic Study

The kinetics of the electroreduction of palladium(II) complexes with -alanine are studied on a dropping mercury electrode in solutions containing various supporting electrolytes (NaF, Na₂SO₄, NaClO₄). The study is carried out at variable concentrations of palladium(II) alaninate complexes, the ligand, and the supporting electrolyte, in the pH interval extending from 3 to 11. The obtained values of the half-wave potential for the electroreduction of palladium(II) complexes with -alanine and the diffusion coefficient for palladium(II) alaninate complexes suggest that, in the acidic and alkaline solutions studied, the slow electrochemical stage involves chelate dialaninate palladium complexes Pd(ala)₂. Palladium(II) complexes underwent reduction on the positively-charged surface of DME without any preceding chemical stages. This process was hindered by anions of the supporting electrolyte adsorbed on DME, and in alkaline solutions, by the alaninate ions as well.     

Photometric determination of palladium with 3-nitroso-2,6-pyridinediol

Summary A highly sensitive and selective photometric method has been developed for the determination of palladium. The method is based on the yellow complex (absorption maximum-430 run) formed when palladium and 3-nitroso-2,6-pyridinediol are heated together in 0.1M perchloric acid. The reaction ratio is 21 reagent to palladium. The molar absorptivity of the yellow complex is 2.6 · 10⁴ liter mole^–1 cm^–1. Only platinum (IV), ruthenium (III), and iron(III) seriously interfere among the common and platinum metals.

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Zusammenfassung Eine sehr empfindliche und selektive photometrische Methode zur Palladiumbestimmung wurde ausgearbeitet. Sie beruht auf dem gelben Komplex (Absorptionsmaximum bei 430 nm), der sich beim Erwärmen aus Palladium und 3-Nitroso-2,6-pyridindiol in 0,1-n Perchlorsäure bildet. Reagens und Metallion reagieren im Verhältnis 21. Die molare Absorption beträgt 2,6 · 10⁴ 1 mol^–1 cm^–1. Nur Platin(IV), Ruthenium(III) und Eisen(III) stören die Bestimmung.

     

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.

     

4(5)-D-Arabinotetrahydroxybutylimidazoline-2-thione (THBIT), a new reagent for the spectrophotometric determination of palladium

Summary 4(5)-D-Arabinotetrahydroxybutylimidazoline-2-thione, THBIT, is proposed as a new reagent for the spectrophotometric determination of Pd(II). Pd(II) forms 11, 12 and 14 complexes with THBIT. The system conforms to Beer's law up to 5g/ml palladium concentration in aqueous medium (molar absorptivity, 1.99×10⁴ l· mole^–1·cm^–1 at 338 nm). The most serious interference is from Hg(II), Os(VIII), Ru(IV), Cr(VI), V(V) and S₂O₃ ^2–. The method has been used successfully for the determination of palladium in catalysts and synthetic samples.     

Triangular silver nanoplates as a spectrophotometric reagent for the determination of mercury(II)

The applicability of triangular silver nanoplates (TNPs) as a spectrophotometric reagent for the determination of mercury(II) in an aqueous solution was estimated. The method is based on the oxidation of TNPs with a mean edge length of 52 nm and thickness of 4 nm by mercury(II) ions, which is accompanied by a decrease in the surface plasmon resonance of nanoparticles. The effect of reaction time, pH of solution, and TNP concentration on the sensitivity of mercury(II) determination was studied. The limit of mercury(II) detection under the selected conditions was 0.022 μg/mL.     

Substoichiometric radiochemical determination of mercury with potassium benzyl xanthate

A sensitive and rapid radiochemical method has been developed for the determination of microgram amounts of mercury by substoichiometric extraction of its 12 complex with potassium benzyl xanthate into chloroform from pH 5.5 acetate buffer. The influence of various foreign ions on the extraction was studied. 2–20 g of mercury was determined with an average error of 1.78%. The method developed was utilized to determine the mercury content of water samples.