Platinum determination by membrane complexation and energy dispersive x-ray fluorescence analysis-A preliminary study

Platinum belongs to the technological metal group of platinum group metals, but it is finding more and more applications these days, especially in automotive catalytic converters and medicine. At the same time, the existing data on its potential toxicity both to humans and to the environment are currently rather limited, and there is also a need to increase the alternative possibilities of its chemical analysis. In this work, an attempt is made for the first time to determine platinum in aqueous samples with energy-dispersive X-ray fluorescence (EDXRF) at low concentrations. For this reason, selective complexing membranes were used that were produced in the context of the present research, after first testing many possible complexing agents. These membranes were fixed on the surface of thin films, immersed in the aqueous samples containing platinum at low concentrations, and after a certain period was collected and analyzed by EDXRF. In addition, other relevant factors such as the distribution of platinum on the membrane surface, the aging of the membrane, the effect of adding salts of various concentrations to the analyzed solution on the improvement of the achieved x-ray yields, the pH, the optimal solution volume and the necessary equilibration time were also investigated. By optimizing all relevant factors, a minimum detection limit of 4 mu g/L was achieved.