Simultaneous Determination Of Platinum Research Articles

DETERMINATION OF PLATINUM AND PALLADIUM IN SOIL AS THEIR CHELATES WITH N,N-DIETHYL-N′-BENZOYLTHIOUREA BY RP-HPLC

A reversed-phase high performance liquid chromatographic (RP-HPLC) method has been developed to separate and determine platinum and palladium in soil after formation of their chelates with N,N-diethyl-N′-benzoylthiourea (DEBT). The method developed does not require the removal of the excess chelating agent and the interfering metals (i.e., Fe and Cu), before the analysis of the two metals in soil. The physical and chemical parameters affecting separation were examined in detail. The whole analysis was completed on a C18 column in 20 min, with the mobile phase of acetonitrile (ACN)-tetrahydrofuran (THF)-water (38:32:30, % v:v:v) containing 0.10 mol L−1 pH 5.0 acetate buffer at a flow rate of 0.8 mL min−1. Absorbance was monitored at 280 nm. Applying a salt-induced phase separation preconcentration method in combination with the proposed chromatographic method, detection limits, based on 3Sb (three times the standard deviation of the blank), were found as 0.014 mg L−1 for palladium and 0.77 mg L−1 for platinum using a 20-µL sample loop. Reproducibility of the method for ten repeated measurements was found as 2.36% for 0.60 mg L−1palladium and 2.58% for 10.0 mg L−1platinum as RSD (%). The proposed method is rapid, simple, and highly selective for the simultaneous determination of platinum and palladium in soil by HPLC.

Simultaneous Determination of Platinum and Rhodium with Hydroxylamine and Acetone Oxime by Catalytic Adsorptive Stripping Voltammetry (CAdSV)

AbstractThis paper describes a very sensitive catalytic adsorptive stripping voltammetry (CAdSV) procedure for the simultaneous determination of traces of platinum and rhodium in new supporting electrolyte containing hydroxylamine or acetone oxime and formaldehyde in sulfuric acid medium. Platinum and rhodium were pre‐accumulated simultaneously and after 120 s of accumulation time at 0.0 V, the achieved detection limits were equal 0.1 ng L−1 and 0.2 ng L−1 for platinum and rhodium respectively in the presence of acetone oxime and 0.6 ng L−1 and 0.2 ng L−1 for platinum and rhodium respectively in the presence of hydroxylamine. Described reagents were successfully applied to the determination of platinum and rhodium in plant material. Inductively coupled plasma mass spectrometry (ICP MS) was used as a reference method to the CAdSV measurements.

Cloud point preconcentration prior to capillary zone electrophoresis: Simultaneous determination of platinum and palladium at trace levels

The incorporation of a cloud point extraction (CPE) step prior to capillary electrophoresis (CE) for simultaneously determining platinum and palladium at sub-microg/L levels is presented and evaluated. The analytes were extracted as 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol complexes, at pH 2.0, mediated by micelles of the nonionic surfactant polyethyleneglycolmono-p-nonylphenyl ether (PONPE 7.5). The separation-determination step was developed from 150 microL of the extracted surfactant-rich phase diluted with 50 microL of acetonitrile (ACN). An exhaustive study of the variables affecting the cloud point extraction with PONPE 7.5 and the CZE step was done. The type and composition of the background electrolytes (BGEs) were investigated with respect to separation selectivity, reproducibility, and stability. A BGE of 50 mM monobasic sodium phosphate containing 30% ACN, pH 4.53 was found to be optimal for the separation of metal chelates. Detection was performed at 576 nm. An enrichment factor of 250 was obtained for the preconcentration of 50 mL of sample solution. The detection limits for the preconcentration of 50 mL of sample were 0.04 microg/L for Pt and 0.08 microg/L for Pd. As an analytical demonstration, ultratrace concentrations of platinum and palladium were conveniently quantitated in spiked water and urine samples.

Simultaneous Potentiostatic Coulometric Determination of Platinum and Palladium

Based on a voltammetric study of the electrochemical behavior of Pt(IV) and Pd(II) in a 1 M HCl + 0.1 M ethylenediamine hydrochloride solution at a carbon–graphite electrode, we have found the optimum conditions for the simultaneous determination of 0.2 to 3 mg of platinum and palladium with a relative standard deviation of less than 0.5%.The oxidation reactions were Pd(0) → Pd(II) and Pt(II) → Pt(IV). Mass excesses of analytes of 3.5- to 4.5-fold with respect to each other did not interfere with the determination of individual elements. With alternate cathodic and anodic polarization of the electrode, these elements can be multiply determined in a single portion of solution. The procedure was used for the simultaneous determination of platinum and palladium in process solutions of KP-1 platinum concentrate after the separation of gold and silver and also in platinum- and palladium-based alloys.

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.

Simultaneous Determination of Platinum(II), Rhodium(III) and Palladium(II) with 2-(5-Bromo-2-pyridylazo)-5-(N-propyl-N-sulfopropylamino)phenol by High Performance Liquid Chromatography

Complexation postcolonne pour determination simultanee du platine, rhodium et palladium par chromatographie HPLC-phase inverse

Spectrophotometric determination of platinum after extraction of its phenanthraquinone monoximate into molten naphthalene

Platinum is determined spectrophotometrically after extraction of its phenanthraquinone monoximate into molten naphthalene in the pH range 2.8–4.1. Beer's law is obeyed in the concentration range 5.0–95.0 µg of platinum in 10 ml of chloroform solution at 425 nm. The molar absorptivity and Sandell's sensitivity are 1.755 × 104 l mol–1 cm–1 and 0.011 µg cm–2, respectively. Ten replicate analyses of a sample solution containing 50 µg of platinum gave a mean absorbance of 0.450 with a standard deviation of 0.0042 and a relative standard deviation of 0.93%. The interference from various ions has been studied and the method has been applied to the simultaneous determination of platinum and palladium in various synthetic mixtures.

Simultaneous determination of platinum(II) and platinum(IV) by controlled-reagent coulometry

Both platinum(II) and the total amount of platinum were determined in the 5-μmole range with a precision of 0.3%. First, platinum(II) was determined dy oxidation with electrogenerated bromine,the equivalent quantity of electricity being measured. After reduction to platinum(II) with electrogenarated tin(II), the total amount of platinum was determined by a second oxidation with electrogenerated bromine.The reduction with tin(II) was too slow for manual control, and an electronic coulometric titrator was used.The construction of the tritator is described. The underlying coulometric principle, called controlled-reagent coulometry, and its adventages are discussed. A number of other substances were also tested.

Simultaneous determination of palladium, platinum and rhodium in crude platinum samples by activation analysis and high-resolution gamma spectrometry

Instrumental neutron-activation analysis using a Ge(Li) detector has been investigated for the simultaneous determination of platinum, palladium and rhodium in crude platinum samples contained in lead cupels. This technique proved feasible and appears promising for extension to the determination of most of the noble metals.

The use of a non-absorbing reference line in the simultaneous determination of platinum, rhodium, palladium and gold by atomic-absorption spectroscopy

A method for determining platinum, rhodium, palladium and gold simultaneously on a direct-reading spectrometer with a non-absorbing reference line is described. The concentration ranges of the working curves were as follows: platinum, rhodium and palladium 0 to 20 p.p.m. and gold 0 to 5 p.p.m. The detection limit for rhodium and palladium was 0·1 p.p.m., for platinum 0·5 and for gold 0·01 p.p.m. The reproducibility of the results was satisfactory.

Spectrophotometric Determination of Platinum with N,N´-Bis(3-dimethylaminopropyl)dithiooxamide. Simultaneous Determination of Platinum and Palladium

Spectrophotometric Determination of Platinum with <i>N</i>,<i>N</i>´-Bis(3-dimethylaminopropyl)dithiooxamide. Simultaneous Determination of Platinum and Palladium