Improved reversed-phase gradient retention modeling.

An empirical nonlinear equation is used to describe the relationship between chromatographic retention and solvent composition in both isocratic and gradient chromatography. The integration of the gradient equation can be solved with our equation, allowing a simple transition between isocratic and gradient conditions. Precise interpolation between experimental data points and reasonable extrapolation outside the directly measured data range are possible.

Peak capacity in unidimensional chromatography.

The currently existing knowledge about peak capacity in unidimensional separations is reviewed. The majority of the paper is dedicated to reversed-phase gradient chromatography, covering specific techniques as well as the subject of peak compression. Other sections deal with peak capacity in isocratic chromatography, size-exclusion chromatography and ion-exchange chromatography.

Differences in preparative loadability between the charged and uncharged forms of ionizable compounds.

Ionizable compounds experience a drastic difference in preparative loadability as a function of pH. It can be shown that the preparative loadability of a compound in the ionic form is by a factor of 20 or more inferior to the loadability of the same compound in the unionized form. In this paper, we demonstrate the reason for this behavior, and show practical applications of the principle.