A group separation method for ruthenium, palladium, rhenium, osmium, iridium, and platinum using their bromo complexes and an anion exchange resin

A new group separation method for Re and PGE (Ru, Pd, Os, Ir, Pt) is descri bed using a novel anion exchange chromatographic resin called TEVA. Re and PGEs are converted into bromo complexes by heating with HF-HBr mixture in a Teflon bomb at 518 K, by in situ-generated Br-2 formed by reaction of HBr and HNO3. Distribution coefficients (K-d) of the bromo complexes onto TEVA resin in 0.1 M HBr with heating at 353 K for one night were 2200, 16000, 16 00, 5500, 4000, and 17 000 for Ru, Pd, Re, Os, Ir, and Pt, respectively, th us allowing 97% recovery of Re and PGEs in 5 mL of solution by 0.1 mL of re sin. These strongly bound Re and PGE bromo, complexes are stripped and reco vered > 90% by the following three steps: (i) addition of 6 M HCl at 353 K and 2.2 M HCl-5 M HBr at 353 K, (ii) heating the resin in 6 M HCl at 353 K to convert the bromo complexes into the chloro complexes with weaker affini ties to the resin; and (iii) sequential addition of the HCl-HBr mixture at room temperature and 7 M HI. Neither the elution profile nor the recovery y ield for a 0.2-g geological sample showed significant changes, indicating m inimal matrix effects for the geological samples. Total blanks were < 14 pg for Ru, Pd, and Pt and < 10 pg for Re, Os, and Jr. Ibis new technique, the refore, is suitable for simultaneous determination of subnanogram per gram of Ru, Pd, Re, Os, Ir, and Pt and Os isotope analysis in geological, minera logical, and environmental samples without direct addition of toxic reagent s required in distillation/extraction of Os or oxidizing of Ir.