Investigation of extraction and back-extraction behaviour of platinum(IV) with rubeanic acid in tributyl phosphate, with tributyl phosphate and with thenoyltrifuoroacetone in n-butyl alcohol-acetophenone by means of platinum-191 radiotracer for platinum-enrichment purposes

The Isotope-Dilution Determination of Platinum in Soil by Inductively Coupled Plasma Mass Spectrometry

A method of the determination of trace amounts of platinum in soils has been developed and validated. Samples were ignited, spiked by 198Pt and decomposed by acid digestion (HF-HClO4, HCl-HNO3). Platinum was separated from the matrix by tellurium coprecipitation (recovery 55-87%) and its content was calculated by the (194Pt + 195Pt + 196Pt)/198Pt ratio measurement. In spite of the separation step (hafnium and tungsten recovery below 1%), residual spectral interference caused by HfO+ ions was observed. This interference as well as that of 198Hg were removed by mathematical correction. Accuracy of the method was confirmed by analysis of certified reference material and by the standard addition method. Detection limit of the method was 0.08 ng g-1 Pt. It was found out that the main component of the standard uncertainty of results was sampling uncertainty. Analysis of soil samples taken in the neighbourhood of Hřensko (Northern Bohemia) showed high platinum contents near the road with heavy traffic.

Use of 191Pt radiotracer for the development of enrichment procedures to detect natural levels of platinum in biological and environmental materials

The 191Pt-radiotracer is a powerful tool to develop separation and preconcentration methods for Pt. The radiotracer was produced either through 190Pt (n, gamma) 191Pt reaction on Pt enriched in 190Pt, or through 191Ir (p,n) 191Pt reaction on natural Ir, followed by Pt/Ir separation. The solvent extraction behavior of 191Pt(IV) from HCl with tributylphosphate, rubeanic acid in tributylphosphate and thenoyltrifluoroacetone in n-butylalcohol/acetophenone, followed by back-extraction with 2 mol/L NH4OH was studied. The overall recovery from a biological matrix is up to 80%. Trace amounts of 191Pt were also preconcentrated as bis-(carboxymethyl) dithiocarbamate chelates on an XAD-4 microcolumn and eluted with EtOH/1 mol/L HNO3. More than 80% is recovered in 2 mL or about 70% in 300 microL.