Quantitative structure-mobility relationship modelling of electrokinetic chromatography of metal complexes: Approaches and limitations

Abstract

A charged surfactant or an ionic polymer added to the capillary electrolyte introduces micellar solubilization and ion-exchange interactions, respectively, as a supplementary separation principle for metal complexes among a great many other analytes. Acting as a pseudostationary phase, such electrolyte additives make the separation mechanism fairly different from that based only on differences in electrophoretic mobility. A range of quantitative structure-mobility relationships were developed to explain the migration behavior of metal complexes in micellar and ion-exchange electrokinetic chromatographic systems as a function of their primary structural parameters. The validity of migration models tested using a comprehensive selection of experimental data available in the literature was shown to depend significantly on the judicious choosing of the analyte structural descriptors and on the dominance of either of the electrophoretic mobility of the analyte, partitioning into the micelle, and the ion-exchange interaction with the polymer. In the systems where the separation mechanism is dominated by neither chromatography nor electrophoresis, their relative contributions were accounted for by the degree of correlation between experimental and calculated mobilities and by variations in the absolute value and sign of regression coefficients at the most influencing parameters.

Prediction of electrophoretic enantioseparation of aromatic amino acids/esters through MIA-QSPR

“…enantiomers) are distinguished by separation methods when standards are not available. Quantitative structure-property relationship (QSPR) modeling has been utilized in the last 10 years for the prediction of retention and migration behaviors [13][14][15][16][17]. Recently, comparative molecular field analysis (CoMFA) has been applied to derive a 3D-QSPR model for the prediction of RMT of a series of enantiomerically pure aromatic amino acids/esters [18].…”

Recent advances in the methodology, optimisation and application of MEEKC

“…81 used MEKC and MEEKC models to predict the log K ow value for uncharged metal complexes and their charged cationic ligands. The authors noted that the partition coefficient has been used to describe metal‐chelate behaviour 84. Also, MEKC has been used to calculate the binding constant between cationic ligands and SDS micelles 85–87.…”

Metal Complex Separation with On-line Sample Preconcentration in Micellar Electrokinetic Chromatography

“…A detailed discussion of the migration behavior of metal complexes can be found in references. 9,35,36 Some MEKC separations of negatively charged metal complexes have been demonstrated with an anionic sodium dodecyl sulfate (SDS) micelle. We first attempted the separation of five negatively charged metal-CDTA complexes using SDS, but did not obtain good separations.…”