Proceedings of the International scientific and practical conference “Science, Technology and Culture: Strategies for Sustainable Development” (December 15-17, 2025) / Publisher website: www.naukainfo.com. – Krakow, Poland, 2025. – 120 p.

10 and reducing the detection limits of elements. In this work, a new solid-phase sorbent was obtained by sequential impregnation of polyurethane foam (PUF) with solutions of 3-phenyl-2,6-dimercapto-1,4-thiopyrone (PhDT) and of Cu(II). PhDT is a dibasic organic acid H 2 L, which in aqueous solutions forms hardly soluble complexes with Pd(II) or Cu(II) ions with a molar ratio of ligand to metal of 1:2. The maximum sorption capacity was determined to be 60.1 μmol/g for PhDT and 29.8 μmol/g for Pd(II) or 31.0 μmol/g for Cu(II) using PUF impregnated with PhDT as a sorbent. In the course of the study, the optimum conditions for solid-phase extraction of Pd(II) using ion-exchange reactions at the interface were determined. The possibility of using heterophase displacement (replacement) reactions to ensure the stability of Pd(II)(HL) 2 complexes formed in the PUF phase was very attractive to us. The Cu(II) complexes with PhDT of the composition Cu(II)(HL) 2 immobilised on the PUF were used for the first time as a solid-phase reagent for the indirect determination of Pd by FAAS. One of the specific methods of concentrating on PUF was used in this study − the pulsating column method. Due to the elasticity of the sorbent, it can be easily compressed (or uncompressed) when the syringe piston moves. The method is very convenient for automated process automation in the sorption−desorption mode. The effectiveness of the dynamic mode of Pd(II) ions concentration under conditions of pumping from 5 to 20 mL of sample through the reaction zone of PUF–Cu(II)(HL) 2 sorbent, the tablet of which was placed in a plastic cylinder of a medical syringe, was established. At the same time, Pd ions in 5 M HCl almost completely (R ≥ 99.8%) displace (elute) Cu(II). The selectivity of the Cu(II) substitution reaction on Pd(II) on PUF was significantly higher than in solution, and a high excess of a number of non- ferrous metals or platinum group metals (Pt and Rh) did not affect the concentration of Pd(II) on PUF.The molar ratio of sorbed Pd(II) to eluted Cu(II) ions was 1:1. Sensitivity of FAAS determination of Cu is higher than for Pd. Using the PUF−Cu(II)(НL) 2 sorbent, it was possible to reduce the limit of detection of Pd by almost 12 times (up to 2.5 μg/L) under conditions of its indirect determination by copper using the FAAS method with the AAnalyst 800 system. The developed methodology was successfully tested for the determination of Pd(II) in a real sample