Separation mechanisms of Co(III) complexes with EDTA-type ligands during salting-out TLC on impregnated and non-impregnated silica gel

Abstract

A separation mechanism of eight Co(III) complexes with ethylenediaminetetraacetate-type ligands belonging to two series during salting-out thin-layer chromatography on silica gel is investigated. The sorbent is impregnated with five poly(ethylene glycol)s with different molecular masses, and ammonium sulphate solutions are used as mobile phase. Additionally, on non-impregnated sorbent, mobile phases containing one of eight salts with ions of different lyotropic properties are used: kosmotropic Mg 2+ accompanied with SO 42- (kosmotrope), Cl - (border), NO 3- (chaotrope), ClO 4-(chaotrope), Cl - of Li + (kosmotrope), Na + (border), K + (chaotrope) and NH 4+ (chaotrope). Salting-out and salting-in effects were observed depending on salt nature. The combined retention mechanism of specific H-bonding and nonspecific hydrophobic interactions is proposed. © 2012 The Author. Published by Oxford University Press. All rights reserved.