Retention behaviour of metal chelates in ion-pair reversed-phase liquid chromatography as a function of mobile phase composition with methanol-water and acetonitrile-water mobile phases

Abstract

The retention behaviour of Cu(II), Co(III), Ni(II) and Fe(II) chelates with 2-(5-bromo-2-pyridylazo)-5-[ N-propyl- N-(3-sulphopropyl) amino]phenol (5-Br-PAPS) and 2-(5-nitro-2-pyridylazo)-5-[ N-propyl- N-(3-sulphopropyl)amino]-phenol (nitro-PAPS) in ion-pair reversed-phase liquid chromatography was examined with mobile phases of methanolwater and acetonitrilewater binary systems containing 0.05 M sodium ion and 0.02 M Tris buffer (pH 7). The correlation of log k′ with the solubility parameter was different between the methanolwater acetonitrilewater systems. The resolution among chelates and reagents was complete with the acetonitrilewater system and far better than with the methanolwater system.