Quantitative structure‐retention relationships in reversed‐phase liquid chromatography using several stationary and mobile phases

Abstract

AbstractQuantitative Structure‐Retention Relationships (QSRRs) have been employed to study retention mechanism of Reversed‐Phase Liquid Chromatography (RPLC). Two C18 and two C8 columns were used with mobile phases containing methanol, acetonitrile, and tetrahydrofuran in concentrations ranging from 40 to 90 (v/v)% in water. QSRR equations derived are generally characterized by a satisfactory quality of fit, although missing data or a low average retention can decrease the goodness‐of‐fit. In agreement with literature the most important retention descriptors appeared to be the analyte's molecular volume and its hydrogen‐bond accepting basicity, but also the polarity/polarizability, hydrogen‐bond donating acidity, and excess molar refraction showed statistical significance in several cases. Relatively small, but significant differences between the two C18 stationary phases were observed. The differences between C8 and C18 column types were more pronounced. The influence of the mobile phase on regression coefficients is more difficult to interpret, because of adsorption of mobile phase constituents by the stationary phase. However, the importance of this partitioning of water and modifier is illustrated by the practically identical trends in b values for the three modifiers studied, while the trends in v values are significantly different. Principal component analysis of the QSRR regression coefficients demonstrated the prevailing role of the mobile phase for chromatographic properties of the RPLC systems studied as compared to the stationary phase.