Platinum In Environmental Samples Research Articles

Spectrophotometric determination of platinum(IV) in alloys, complexes, environmental, and pharmaceutical samples using 4-[N,N-(diethyl)amino] benzaldehyde thiosemicarbazone

4-[N,N-(Diethyl)amino] benzaldehyde thiosemicarbazone (DEABT) is proposed as an analytical reagent for the spectrophotometric determination of platinum(IV). The DEABT forms 1:2 yellow complex with Pt(IV), which is sparingly soluble in water and completely soluble in water-ethanol-DMF medium. The Pt(IV)-DEABT complex shows maximum absorbance at 405 nm. Beer's law is valid up to 7.80 μg cm(-3), and optimum concentration range for the determination of platinum(IV) is 0.48-7.02 μg cm(-3). The molar absorptivity and Sandell's sensitivity of the method are found to be 1.755 × 10(4) dm(3) mol(-1) cm(-1) and 0.0012 μg cm(-2), respectively. The relative error and coefficient of variation (n=6) for the method does not exceed ± 0.43% and 0.35%, respectively. Since the method tolerates a number of metal ions commonly associated with platinum, it can be employed for the determination of platinum in environmental samples, pharmaceutical samples, alloys, catalysts, and complexes. The method is rapid as the Pt(IV)-DEABT complex is soluble in water-ethanol-DMF medium and not requiring any time consuming extraction method for the complex.

Internal correction of hafnium oxide spectral interferences and mass bias in the determination of platinum in environmental samples using isotope dilution analysis

A method has been developed for the accurate determination of platinum by isotope dilution analysis, using enriched (194)Pt, in environmental samples containing comparatively high levels of hafnium without any chemical separation. The method is based on the computation of the contribution of hafnium oxide as an independent factor in the observed isotope pattern of platinum in the spiked sample. Under these conditions, the ratio of molar fractions between natural abundance and isotopically enriched platinum was independent of the amount of hafnium present in the sample. Additionally, mass bias was corrected by an internal procedure in which the regression variance was minimised. This was possible as the mass bias factor for hafnium oxide was very close to that of platinum. The final procedure required the measurement of three platinum isotope ratios (192/194, 195/194 and 196/194) to calculate the concentration of platinum in the sample. The methodology has been validated using the reference material "BCR-723 road dust" and has been applied to different environmental matrices (road dust, air particles, bulk wet deposition and epiphytic lichens) collected in the Aspe Valley (Pyrenees Mountains). A full uncertainty budget, using Kragten's spreadsheet method, showed that the total uncertainty was limited only by the uncertainty in the measured isotope ratios and not by the uncertainties of the isotopic composition of platinum and hafnium.

Assessment of immobilized yeast for the separation and determination of platinum in environmental samples by flow-injection chemiluminescence and electrothermal atomic absorption spectrometry

The yeast Saccharomyces cerevisiae immobilized in calcium alginate beads was used for separation and subsequent determination of Pt in environmental samples by flow-injection chemiluminescence (FI-CL) and electrothermal atomic absorption spectrometry (ETAAS). The application of a yeast column resulted in an increase in the tolerable matrix ions concentration compared to direct measurements by both detection techniques. The developed FI-CL method of Pt determination based on the catalytic effect of Pt(IV) ions on luminol oxidation in alkaline medium is characterized by a low limit of detection (0.15 ng mL−1), and good sensitivity and precision, and can be used for analysis of Pt in water samples. Determination of Pt in more complex environmental samples can be carried out by ETAAS (LOD = 6 ng mL−1) after introduction of a column clean-up step with 10 mM nitric acid. The accuracy of the method was confirmed by analyzing the certified reference material of platinum ore (SARM-7), spiked grass, and road dust samples.

Determination of rhodium and platinum by electrothermal atomic absorption spectrometry after preconcentration with a chelating resin

The present publication describes a separation/preconcentration procedure for the subsequent trace analysis of rhodium and platinum in environmental samples. A chelating ion-exchange resin was employed for this purpose and an automatic on-line flow injection electrothermal atomic absorption spectrometry (FI-ET-AAS) method was used for the determination of trace amounts of Rh and Pt in different materials. The solutions are simultaneously treated and the ions determined sequentially. Detection limits of rhodium and platinum are 0.8 and 1.0 ng mL-1, respectively. Linearity was obtained in the range 0-50 ng mL-1 for rhodium and 0-100 ng mL-1 for platinum. The relative standard deviations were 1.8% for 10 ng mL-1 of Rh and 1.6% for 10 ng mL-1 of Pt. Enrichment factors were 20 for Rh and 14 for Pt.

Preconcentration of Trace Amounts of Platinum in Environmental Samples on Different Sorbents: A comparative study

Since the introduction of the catalytic cleaning of vehicle exhaust gases, platinum is discussed as environmentally relevant element. Increasing Pt concentrations have been reported from a number of countries. The determination of platinum in biological and environmental materials at the “natural” level was made possible by the development of extremely sensitive analytical methods. Two different sorbents for platinum preconcentration in catalyst, water, soil and vegetation were investigated: silica gel functionalized with 1,5-bis(di-2-pyridyl)methylene thiocarbohydrazide (DPTH-gel) and [1,5-Bis(2-pyridyl)-3-sulphophenyl methylene thiocarbonohydrazide (PSTH) immobilised on an anion-exchange resin (Dowex 1x 8-200)]. The sorbents were tested in a microcolumn, placed in the autosampler arm, at the flow rate 2.4 ml min. Elution was performed with 2 M nitric acid. Satisfactory results were obtained for two sorbents.

Determination of Platinum at Trace Levels in Environmental and Biological Materials

The treatment of exhaust gases from motor vehicles equipped with autocatalytic converters has resulted in the removal of about 90% of carbon monoxide, unburned hydrocarbons, and nitrogen oxides from the exhaust. However, contamination of the environment occurs in the form of airborne particulate material (or dust) from the abrasion and deterioration of the catalysts. The dust contains precious metals, mainly platinum together with palladium and rhodium. It is deposited along the roadways, on soil and vegetation, and in bodies of water. Sensitive analytical methods are required for determinations of very low levels of platinum in environmental samples in order to ascertain the extent and the seriousness of this relatively new source of pollution. The difficulties in obtaining accurate results in analyses even for total platinum concentrations are formidable. This review is a summary of recent research on the determinations of platinum and other precious metals in dust, vegetation, soil, water, and biologic...

An Improved Anion-Exchange Separation for the Determination of Platinum in Environmental Samples by Inductively Coupled Plasma Mass Spectrometry

Abstract A new and practical column separation/preconcentration method for the determination of Pt in environmental samples is proposed. The method has been successfully applied to the determination of Pt in a tunnel dust sample with isotope dilution ICP-MS. A key to its success is an anion-exchange separation of Pt from Hf.