Determination of platinum metals by x-ray fluorescence, atomic emission and atomic absorption spectrometry after preconcentration with a polymeric thioether

Abstract

A method for preconcentration of platinum metal based on their sorption by a polymeric thioether (—CH 2S—) n is reported. The method is characterized by selectivity, high recovery and simplicity, and is suitable for a wide range of platinum metal concentrations; light non-ferrous metals do not interfere. The concentrate can be analyzed either directly or after rapid dissolution. The sorbent has a high capacity for platinum metals. X-ray fluorescence is suitable for determination of the metals in the concentrate after it has been compressed. This method provides a high precision in the determination of platinum metal ( s r = 0.02–0.04 for 250 μg −1). Electrothermal atomic absorption spectrometric methods can be applied to be concentrates with or without prior dissolution; these allow the determination of platinum metals even at the 1 ng ml −1 level in technical logical solutions and at the 0.1 ng g −1 level in solid products ( s r = 0.18). The concentrate can be also subjected to atomic emission spectrometry either with the inductively-coupled plasma after dissolution or with an arc discharge without dissolution. These methods allow the determination of platinum metal (0.1–100 μg ml −1 in technical solutions; the precision ( s r) is 0.01–0.04 when the plasma is used.