Effective removal and quantitative analysis of Pd, Cu, Ni, and Pt catalysts from small-molecule products

We demonstrate the ability of N,N-diethylphenyl-azothioformamide and N,N-bis[tetra(ethylene glycol)monomethyl ether]phenylazothioformamide ligands to dissolve the four transition metals: palladium, copper, nickel and platinum. The method allows solubilisation and quantitative analysis of the transition-metal content in their bulk metallic forms and as nanoparticles produced during their use as catalysts in Sonogashira coupling reactions.