**10. Ion exchangers of functional (amino)pyridine groups**

Resins of pyridine [81] and α-aminopyridine groups on the polyphenylethylene support [82] were successfully used for the separation of technetium and platinum metals from diluted chloride solutions and in concentration of Pt(IV), Pd(II) and Ir(III) (*on-line* FAAS). Technetium ions were eluted using concentrated solutions of hydrochloric acid but platinum metals (Ru(III), Rh(III) and Pd(II)) by means of 0.1 M NH2CSNH2 in 1 M HCl [81] or 0.5 M HCl – 0.5 M HClO4 – 0.5 M Mg(ClO4)2 [82]. Most interferences coming from noble-metal ions were eliminated using 2 M HCl and those from iron (> 200 mg Fe/dm3 ) adding 0.2 M EDTA [82].