title: An advanced application of the quantitative structure-activity relationship concept in electrokinetic chromatography of metal complexes.
abstract: The relevance of the quantitative structure-activity relationship (QSAR) principle in MEKC and microemulsion EKC (MEEKC) of metal-ligand complexes was evaluated for a better understanding of analyte migration mechanism. A series of gallium chelates were applied as test solutes with available experimental migration data in order to reveal the molecular properties that govern the separation. The QSAR models operating with n-octanol-water partition coefficients or van der Waals volumes were found to be valid for estimation of the retention factors (log k') of neutral compounds when using only an aqueous MEEKC electrolyte. On the other hand, consistent approximations of log k' for both uncharged and charged complexes in either EKC mode (and also with hydro-organic BGEs) were achievable with two-parametric QSARs in which the dipole moment is additionally incorporated as a structural descriptor, reflecting the electrostatic solute-pseudostationary phase interaction. The theoretical analysis of significant molecular parameters in MEKC systems, in which the micellar BGE is modified with an organic solvent, confirmed that concomitant consideration of hydrophobic, electrostatic, and solvation factors is essential for explaining the migration behavior of neutral metal complexes.
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, Warsaw University of Technology, Warsaw, Poland.
authors.forename: Sławomir
authors.initials: S
authors.lastname: Oszwałdowski
authors.forename: Andrei R
authors.initials: AR
authors.lastname: Timerbaev
mesh_terms: D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D005708:Gallium / Q000737:chemistry*; D008823:Micelles; D008962:Models, Theoretical; D021281:Quantitative Structure-Activity Relationship; D055672:Static Electricity
chemical_list: D008823:Micelles; D005708:Gallium