Analytical study of the phenyl-2-pyridyl ketone azine-palladium system. Photometric determination of palladium

Phenyl-2-pyridyl ketone azine reacts with palladium(II) to produce a yellow 1:1 complex (λ_max = 425 nm, ? = 10.4 × 10³M^?1 cm^?1 in aqueous ethanolic solution) and a red-violet 3:1 complex (λ_max = 530?540 and 380?390 nm). The yellow complex in aqueous ethanolic solution has been used for the spectrophotometric determination of trace amounts of palladium. The method has been applied to the determination of palladium in some catalysts and one mineral.     

Extractive spectrophotometric determination of palladium with N,N,N',N'-tetra(2-ethylhexyl)-thiodiglycolamide T(2EH)TDGA

A precise, sensitive and selective method for the spectrophotometric determination of palladium (II) using N,N,N′,N′-tetra(2-ethylhexyl) thiodiglycolamide T(2EH)TDGA as an extractant is described. Palladium (II) forms yellow colored complex with T(2EH)TDGA which exhibits an absorption maximum at ∼300 nm. The colored complex obeys Beer's law in the concentration range 1.0-15.0 μg ml⁻¹ of palladium with a molar absorptivity of 1.29 × 10⁵ M⁻¹ cm⁻¹. The effects of various experimental parameters have been studied to establish the optimum conditions for the extraction and determination of palladium. The precision of the method has been evaluated and the relative standard deviation has been found to be less than 0.5%. The method has been successfully applied to the determination of palladium in simulated high level liquid waste (SHLW) solution.     

Palladium and the electrochemical quartz crystal microbalance: a new method for the in situ analysis of the precious metal in aqueous solutions

A new method for the quantitative determination of palladium(II) by the electrochemical quartz crystal microbalance (EQCM) technique has been developed. Using a bare carbon-coated quartz crystal, Pd(II) ions are directly deposited from aqueous solution as palladium metal onto the crystal surface, and the Pd(II) concentration is determined with a detection limit of 0.0156 mM, or 1.66 ppm. No complexing agent or preconcentration of palladium is required for the analysis. The palladium is stripped from the crystal through its electrochemical oxidation, regenerating the crystal for subsequent multi-cycle palladium analyses. A conventional gold-coated quartz crystal was incapable of carrying out the same measurements. The EQCM technique presented is simple, sensitive, and reproducible for the detection of this widely used precious metal.     

Nonpyridinic derivatives in C-5 of 2-thiohydantoin for spectrophotometric determination of palladium

The reactions between Pd(II) and four nonpyridinic derivatives of 2-thiohydantoin (5-benzal-2-thiohydantoin, 5-(o-hydroxy)benzal-2-thiohydantoin, 5-(m-hydroxy)benzal-2-thiohydantoin, and 5-anisal-2-thiohydantoin) have been considered. The influence of the different experimental parameters on the formation of the complexes was studied, and the optimum conditions for the determination of palladium were established. The anisal derivative was selected among these four reagents and the spectrophotometric determination of palladium described in detail. The precision of the procedure, expressed in terms of relative standard deviation was 0.9%, and numerous ions that usually interfere in palladium determination, such as Os(VIII), Rh(III), and Ru(IV) (of the platinum group) and Pb(II), Cd(II), Ni(II), Co(II), Zn(II), and others of the transition series, were tolerated.     

Dispersive liquid-liquid microextraction preconcentration of palladium in water samples and determination by graphite furnace atomic absorption spectrometry

A new method for the determination of palladium was developed by dispersive liquid-liquid microextraction preconcentration and graphite furnace atomic absorption spectrometry detection. In the proposed approach, diethyldithiocarbamate (DDTC) was used as a chelating agent, and carbon tetrachloride and ethanol were selected as extraction and dispersive solvent. Some factors influencing the extraction efficiency of palladium and its subsequent determination, including extraction and dispersive solvent type and volume, pH of sample solution, concentration of the chelating agent and extraction time, were studied and optimized. Under the optimum conditions, the enrichment factor of this method for palladium reached at 156. The detection limit for palladium was 2.4 ng L⁻¹ (3σ), and the relative standard deviation (R.S.D.) was 4.3% (n = 7, c = 1.0 ng mL⁻¹). The method was successfully applied to the determination of trace amount of palladium in water samples.     

Analysis of Sub-Microgram Levels of Palladium (II) in Environmental Samples by Selective Extraction and Spectrophotometric Determination with N-p-Methoxyphenyl-2-Furylacrylohydroxamic Acid and 5-(Diethylamino)-2-(2-Pyridylazo) Phenol

Abstract

Nine new hydroxamic acids in conjunction with four pyridylazo reagents were explored for extractive separation and spectrophotometric determination of palladium in environmental samples. It was found that maximum sensitivity and selectivity was achieved by employing N-p-methoxyphenyl-2-furylacrylohydroxamic acid (MFHA) and 5-(diethylamino)-2-(2-pyridylazo) phenol (DEPAP). Palladium was first selectively extracted with MFHA in isoamyl alcohol at pH 2.7-3.5 and the extract was equilibrated with a mixture of 5 M HCl and 10^{? 3} M solution of DEPAP in ethanol. The resulting intensely green ternary complex was measured at 560 nm (σ 5.1 × 10⁴ l mole^?1 cm^?1). The extraction system is suitable for enrichment of palladium over 15 times without loss in recovery and enables determination of palladium at levels as low as 10^?4 ppm (0.1 ppb). The method tolerates the presence of a large number of diverse ions normally associated with palladium, including platinum metals, and was employed for the determination of palladium in standard catalysts, biological materials, and freshwaters.     

Determination of trace impurities in some nickel compounds by flame atomic absorption spectrometry after solid phase extraction using Amberlite XAD-16 resin

A simple flame atomic absorption spectrometric (FAAS) procedure for the determination of lead, bismuth, gold, palladium and cadmium as impurities in Raney nickel and nickel oxide was developed using a preconcentration step on an Amberlite XAD-16 resin packed column. Lead, bismuth, gold, palladium and cadmium were quantitatively recovered and separated from a solution containing 1 M HCl and 0.3 M NaI by the column system. Effects of the various parameters such as reagent concentrations, sample volume, matrix effects, etc. have been investigated. Under optimized conditions, the relative standard deviation of the combined method of sample treatment, preconcentration and determination with FAAS (n = 7) is generally lower than 12%. The limit of detection (3s, n = 20) was between 10–270 ng/g. The results were used for separation and preconcentration of five trace elements from nickel matrices.     

Spectrophotometric determination of palladium by solvent extraction as the Pd(II)-biacetylmonoxime 2-pyridylhydrazone complex

Determination of trace levels of palladium(II) is described. The method relies upon the extraction of palladium(II)-biacetylmonoxime 2-pyridylhydrazone (BMPH) from aqueous acidic solution into chloroform to form a purple-reddish complex. The molar absorptivity of the Pd-BMPH complex is about 7500 liters mol^?1 cm^?1 at 560 nm in the chloroform extract. The highly colored chloroform extract is suitable for spectrophotometric determination. The method devised has been applied to the determination of palladium in $\text{Pd}\text{CaCO}{}_3$ catalyst with good results.     

Application of thiophene-2-carbaldehyde-modified mesoporous silica as a new sorbent for separation and preconcentration of palladium prior to inductively coupled plasma atomic emission spectrometric determination

A new and efficient method was described for an easy synthesis of functionalized mesoporous silica (MCM-41) using thiophene-2-carbaldehyde. This new chemically bonded analytical reagent was used as an effective sorbent for the solid phase extraction of palladium(II) ion from aqueous solutions. Conditions for effective adsorption of trace levels of palladium concentration were optimized with respect to different experimental parameters in batch process. Thiourea solution could efficiently elute adsorbed palladium(II) ion from the surface of the sorbent which then was determined by inductively coupled plasma atomic emission spectrometer (ICP-AES).Common coexisting ions did not interfere with the separation and determination. The preconcentration factor was 100 (1 ml elution volume) for a 100 ml sample volume. The limit of detection of the proposed method is 0.2 ng ml⁻¹. The maximum sorption capacity of sorbent under optimum conditions has been found to be 5 mg of palladium per gram of sorbent. The relative standard deviation under optimum conditions was 3.2% (n = 10). Accuracy and application of the method was estimated by using test samples of natural and synthetic water spiked with different amounts of palladium(II) ion.     

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.     

Simultaneous Determination of Platinum and Palladium by Second Derivative Spectrophotometry Using 3-(2'-Thiazolylazo)-2, 6-Diaminopyridine as Chromophore Ligand

ABSTRACT

A second derivative spectrophotometric method has been developed for the determination of palladium and platinum in mixtures. The method is based on the formation of the platinum and palladium complexes with 3-(2-thiazolylazo)-2, 6-diaminopyridine, (2, 6-TADAP), in the presence of 1.7 M perchloric acid solution, upon heating at 90° C for 30 min and on the subsequent direct derivative spectrophotometric measurement. The zero-crossing approach and the graphic method were used for determination of platinum and palladium, respectively. Each analyte was determinated in the presence of one another in the ranges 8.9×10^-7 -3.1×10^-5 M for platinum and 4.6×10^-7 - 6.8×10^-5 M, for palladium. The detection limits achieved (3a) were found to be 2.7×10^-7 M of platinum and 1.4×10^-7 M of palladium. The relative standard deviations were in all instances less than 1.0%. In this work is included a study of effect of interferents and the application of the proposed method in synthetic mixtures.     

The simultaneous determination of copper and nickel by solvent extraction and gas-liquid chromatography with bis (acetylpivalylmethane) ethylenediimine as reagent

The copper(II), nickel(II) and palladium(II) chelates of the bridged β-ketoamine, bis(acetylpivalylmethane) ethylenediimine, are described. The copper and nickel complexes are readily extracted by cyclohexane at pH 8.0 from aqueous solution. The gas chromatographic separation of the copper and palladium, the nickel and palladium, and the copper and nickel chelates is reported on a silicone gum rubber phase (E-350) supported on Universal B at 285°C. Optimal conditions for the complete separation of copper and nickel are reported; the solvent extraction—gas chromatographic procedures are applied to the determination of the individual metal ions (limit of detection, 1 ng) and to the simultaneous determination of copper and nickel in solution and in alloy samples. A rapid method for the determination of copper in domestic water samples is also described.     

Spectrophotometric determination of palladium with glyoxime and chloroform extraction

Palladium(II) reacts with glyoxime in a 1:2 mole ratio to form a yellow water-insoluble chelate, which is soluble in chloroform; the solution has an absorption maximum at 397 mμ. Absorbance measurements at 397 mμ allow determination of the palladium glyoximate in solution. The maximum amount of palladium is extracted at pH 1.0. Platinum(II), iridium(III), gold(III), and phosphate cause some positive interference, and iron(II, III) causes negative interference; the interferences can be eliminated by masking with EDTA. The species extracted has been shown to be identical with that used to prepare the original palladium glyoximate chloroform solution. With EDTA and multiple extractions, the method is satisfactory for the determination of palladium in the presence of other platinum-group elements and many other cations.     

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.     

The extractive spectrophotometric determination of palladium(ii) as the mixed-ligand complex with picolinealdehyde-2-hydroxy-5-phenylanil and chloride ion

The extraction of palladium(II) with chloroform in the presence of PHPA and chloride ions is described. The extracted species has an absorption maximum at 627 nm, and Beer's law is obeyed over the range 10–200 μg of palladium. The molar absorptivity is 4.90·10³ l mol^?1 cm^?1 at 627 nm. The 1:1:1 Pd(PHPA)-Cl complex is extracted from aqueous solution. The effect of foreign ions on the determination of palladium(II) is examined.     

催化动力学光度法测定痕量钯

在磷酸－磷酸二氢钾缓冲溶液中，以钯（Ⅱ）催化次磷酸钠还原罗丹明Ｂ褪色为指示反应，建立了痕量钯的动力学光度分析新方法。在金（Ⅱ）的存在下，检测下限达５×１０＾－１１ｇ／ｍＬ钯（Ⅲ），方法应用于模拟合金样和含钯分子筛中钯的测定。结果满意。     

Simultaneous Laser Thermal Lens Spectrometric Determination of Trace Platinum and Palladium in an Aquesous Solution

A selective and sensitive method for determination of platinum and palladium(Ⅱ）in an aqueous solution simultaneously by laser thermal lens spectrometry,based on the complex reaction of 2-(3,5-dichloropyridylazo)-5-dimethylaminoamiline(3,5-diCl-PADMA) with platinum and palladium,has been developed.It is shown that the palladium complex can be fromed at room temperature, while the platinum complex can be only formed after being heated in a boiling water bath.By using this difference of reaction temperature and the characteristic of the complexes mentioned above,the method for simultaneous determination of platinum and palladium was established in an aqueous solution without a pre-separation.The results show that the dynamic linear ranges of determination for platinum and palladium are 0.005-0.04μg/mL and 0.005-0.25μg/mL respectively,and that the detection limits are both 0.002/μg/mL.The method has been applied to the determination of platinum and palladium simultaneously in alloy and catalyst samples with satisfactory results.     

Determination of palladium(II) using thiosemicarbazide as a replacing reagent

A simple, rapid, accurate, and selective complexometric method is proposed for the determination of palladium(II). Palladium(II), with associated diverse metal ions, is first complexed by adding a known excess of EDTA, and the uncomplexed EDTA is back titrated with lead nitrate solution in acetic acid-sodium acetate buffer (pH 5.0–6.0) until the end-point. Thiosemicarbazide (1%) solution in water is added to displace EDTA from the Pd-EDTA complex. The released EDTA is then titrated with the lead nitrate solution. Reproducible and accurate results are obtained in the concentration range of 1–10 mg of palladium with a relative error of less than 0.4% and a standard deviation of less than 0.02. The interference of many commonly associated metal ions was also studied. Advantages of this method over other complexometric methods of palladium determination are high-lighted.     

Derivate von salicylketonen1: Mitt. schiffsche basen aromatischer o-aminoketone mit ǎthylendiamin und ihre analytische anwendung zur nickelbestimmung

Schiff bases from ethylenediamine with o-aminoacetophenone or o-aminoben-zophenone were prepared, and their chelating properties towards copper, nickel, cobalt, iron, palladium and platinum were studied. The use of the ligands for the photometric determination of metals was tested. A method for the determination of nickel with N,N'-bis(o-aminoacetophenone)-ethylenediimine was developed. Masking agents prevent the interference of iron and copper; a 25-fold amount of palladium and a 10-fold amount of cobalt can be tolerated.     

Influence of Masking Agents on the Color Reactions of Dithizone with Pd(II), Hg(II), and Ag(I) Ions after the Sorption of Their Chloride Complexes on the Fibrous Filled Anion Exchanger AV-17

The influence of masking agents (acetate, thiosulfate, tartrate, and iodide ions; thiourea; and ethylenediaminetetraacetic acid (EDTA)) in a dithizone solution on the complexation of Hg(II), Pd(II), and Ag(I) ions on the solid phase of the fibrous anion exchanger filled with AV-17 was studied. Mercury, palladium, and silver were adsorbed as chloride complexes. The possibility of the simultaneous group determination of the three elements and the selective determination of palladium in the presence of mercury and silver by measuring the diffuse reflection coefficient at two wavelengths (580 and 680 nm, respectively) was demonstrated. A mixture of dithizone with EDTA, acetate, iodide, or thiosulfate can be used for masking concomitant elements. The reaction of palladium with dithizone on the solid phase can be used for the test determination of palladium with the detection limit 0.01 mg/L.