Test Analytes for Studies of the Molecular Mechanism of Chromatographic Separations by Quantitative Structure−Retention Relationships

Abstract

Three model series of nonionized in water analytes are proposed for objective interlaboratory comparisons of effects on chromatographic separations of the stationary and the mobile phases by means of the analysis of quantitative structure-retention relationships (QSRR). Each series was designed specifically for a given general QSRR model by selecting the analytes whose properties were well reflected by the respective structural descriptors. Rules of a meaningful chemometric analysis were observed, and the structural information content was compromised with the length of analyte series. Three QSRR models were verified and are recommended for studies of molecular mechanism of chromatographic retention: the reduced linear solvation energy relationship-based model of Abraham, a model employing structural descriptors from molecular modeling, and a model correlating retention to the 1-octanol-water partition coefficient, log P. All the models were demonstrated to provide reliable QSRR equations for five sets of diverse retention data. These equations discriminate quantitatively individual chromatographic systems and are interpretable in straightforward chemical categories. In view of QSRR analysis, the retention processes clearly emerge as the net effects of fundamental intermolecular interactions involving the analyte and the components of chromatographic systems.

Chemometric outlook on correlations between retention parameters of polar and semipolar HPLC columns and physicochemical characteristics of ampholytic substances of biological and pharmaceutical relevance

“…Since the analyzed compounds exhibit common property that is ampholyticity, but are significantly structurally diversified, we selected the abovementioned QPRR method, instead of more often applied QSRR (Quantitative StructureRetention Relationship) approach [12][13][14][15][16]. We do so, having in mind that many drugs possessing similar structure exhibit different therapeutic features [17,18].…”

Simultaneous Effect of Organic Modifier and Physicochemical Parameters of Barbiturates on their Retention on a Narrow-Bore PGC Column. Part 2

“…These linear QSRR methods have been recently employed in chromatography for the investigation of the molecular mechanism of separation, 13 for the classification of modern stationary phases, 14 for structure-retention relationship study in HPLC 15 and in GC, 16,17 and for the elucidation of the correlation between retention and biological activity. 18 Stepwise regression analysis (SRA) is an up-to-date version of multivariate linear regression analysis.…”

Use of Kernel Orthogonal Projection to Latent Structure in Modeling of Retention Indices of Pesticides

“…However, temperature programmed retention indices (TPRI) seem to be more useful in analysis of more complex mixtures such as pesticides. The study of quantitative structure -retention relationship (QSRR) of solutes is an important topic in chromatographic thermodynamics [9,10]. Various kinds of successful models (linear and nonlinear) are applied to predict the retention indices of several classes of compounds [11 -14].…”