Snyder-Soczewinski model of adsorption chromatography

As can be easily deduced, quantification of sorbent activity cannot be done in the absolute, but in relative values only. The most complete approach to this problem was derived from the Snyder-Soczewinski model of adsorption chromatography, and it will be briefly discussed here. 

Quantification of solvent elution strength is based on the Snyder-Soczewinski model of adsorption chromatography. A possibility of appropriate quantification is offered by Eq. 47. For the sorbent activity coefficient a = 1, Eq. 47 can be rewritten in the following form ... 

Two very simple relationships have been derived from the general framework of the Snyder and Soczewinski model of adsorption chromatography these have proved useful for rapid prediction of solute retention in chromatographic systems employing binary mobile phases. One (known as the Soczewinski equation) proved successful for adsorption and normal-phase TLC the other (known as the Snyder equation) proved similarly successful in reversed-phase TLC. 

The semiempirical model of adsorption chromatography, analogous to that of Martin and Synge, was established only in the late 1960s by Snyder [3] and Soczewinski [4] independently, and it is often referred to as the displacement model of solute retention. The crucial assumption of this model is that the mechanism of retention consists in competition among the solute and solvent molecules for the active sites of the adsorbent and, hence, in a virtually... 

The retention model in adsorption chromatography developed by Snyder and Soczewinski is based on the assumption that there is flat adsorption in a monomolecular layer on a homogeneous adsorption surface. The adsorption is understood as a competition phenomenon between the molecules of the solute and the solvent on the adsorbent surface, so that the retention of a sample molecule requires the displacement of one or more previously adsorbed polar solvent molecules. Later, the model was corrected for adsorption on a heterogeneous surface of adsorbent. To first approximation, the solute-solvent interactions in the mobile and stationary phases are assumed to compensate each other and possible liquid-liquid partition effects are neglected. In this case, the retention in a mixed binary mobile phase comprising a nonpolar solvent, A (usually an aliphatic hydrocarbon), and a polar solvent, B, can be described by eqn [1] ... 

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