Application of excess adsorption data measured for components of the mobile phase for characterizing chromatographic systems

A new equation for the retention of solutes in liquid–solid adsorption chromatography with mixed mobile phases

“…A related method of combining chromatographic data with liquid adsorption measurements for examining theoretical models for the capacity ratio in LSC was published by Jaroniec and Okik-Mendyk. 14 The present work demonstrates clearly that the retention of the solutes is correlated with the surface concentration of the more strongly adsorbed component of the solvent system, and the new equation accounts for the observed dependence of the capacity ratio on the composition of the mobile phase in a reasonable way.…”

“…The above expression for yf results from the assumption that molecules in the adsorbed monolayer interact not only with their neighbours in the surface layer but also with molecules in the adjacent layer of the liquid phase (Ap and Av denote fractions of nearest neighbours to a given lattice site in the same layer and in each of the adjacent layers parallel to the surface). With this definition of the surface activity coefficients the function g,, of eqn (14) becomes…”

“…The experimental data show k; for phenanthrene eluted by the solvent system C-D. The curves were obtained by eqn (20) and are based on the surface concentration isotherm x; =Ax;) given by eqn (14), with the parameters of table 1. For all curves, p = 0.08 and S,, = 1.1 has been chosen (see below), and the best-fit value of the size parameter r, was calculated by an iterative procedure.…”

Selectivity in normal-phase liquid chromatography with binary mobile phase

“…As a consequence, the function Y (x 1 ), that describes the distribution of the polar solvent between the stationary and mobile phases, is independent of the solute. It can be estimated immediately from adsorption measurements (Jaroniec and Ościk-Mendyk 1981) or calculated from the well-known theoretical isotherm proposed by Everett (1964) …”

“…Numerous models have been developed to describe the retention in liquid solid chromatography with mixed mobile phases, several reviews cover the results (Borówko 2002;Jaroniec 1983a, 1983b;Jaroniec et al 1985;Nurok 1989;Snyder 1969;Soczewiński 2002). These approaches involve various factors, namely, interactions with the surface Jandera et al 2001;Jaroniec et al 1978;Scott and Kucera 1975;Snyder and Glajch 1981), non-specific interactions in the liquid phase (Boehm and Martire 1980;Borówko 1984) association and solvation effects Jaroniec 1983a, 1983b;Jaroniec et al 1985) differences in molecular sizes of components (Borówko 1986)), energetical heterogeneity of the adsorbent (Borówko 2002;Borówko and Jaroniec 1979;Jaroniec and Ościk-Mendyk 1981), orientation of solute molecules on the surface (Borówko 1988), etc. Nevertheless, theoretical aspects of liquid adsorption chromatography still remain a matter of the debate in the literature.…”