Development of an eluotropic series for the chromatography of Lewis bases on zirconium oxide

Abstract

Ligand-exchange interactions, which dominate the retention characteristics of Lewis base solutes on zirconium oxide, can be strongly attenuated by the addition of a competing Lewis base to the eluent. The chromatographic effects of these competing bases vary significantly in their thermodynamics and kinetics depending on their structure and Lewis basicity. An eluotropic scale of mobile-phase strength for ligand-exchange/ion-exchange chromatography on zirconia has been developed which ranks the overall elution strength of a variety of Lewis bases in terms of their ability to elute a wide variety of benzoic acid derivatives. This series generally holds true for similar solutes; however, deviations are noted with some solutes and eluents where chelation and steric factors alter the kinetic and thermodynamic characteristics of the retention process.

Synthesis and characterization of titania based stationary phases using the silanization/hydrosilation method

“…This property has been demonstrated for alumina that was modified by bonding with organophosphates [6] as well as coated with polybutadiene [7]. A similar result was obtained for zirconia which also was shown to provide good separations of solutes such as polycyclic aromatic hydrocarbons, nucleotides and proteins [8][9][10]. The reverse phase properties of the modified zirconia were shown to be similar to that of silica containing bonded hydrophobic moieties [10,11].…”

Impact of column temperature and mobile phase components on selectivity of hydrophilic interaction chromatography (HILIC)

“…For example, Zirconia, i. e. zirconium oxide, is an amphoteric metal oxide, which exhibits both anion-and cation-exchange properties depending on the solution pH and the nature of the buffer [47]. When 50% ACN plus 50 mM phosphate buffer (pH 2.0) was used to separate pentapeptides the separated analytes are positively charged resulting in the domination of ionexchange interactions with adsorbed phosphate on the zirconia surface over hydrophobic interactions with PBD, polybutadiene, or PS, polystyrene, coatings.…”

Utilization of zirconia stationary phase as a tool in drug control

“…One of the most chemically interesting aspects of using zirconia supports is that of their surface chemistry, which is radically different from that of silica supports. In particular, there are many hard Lewis acid sites on the zirconia surface [29,30]. In aqueous media the surface is populated with hydroxylated and aquated Zr(IV) sites which can undergo ligand exchange with hard Lewis bases.…”