Apparent transfer parameters relevant to the static equilibrium experiment and gel chromatography

1 Apparent transfer parameters relevant to the static equilibrium experiment and gel chromatography 

Prior to the evaluation of solubility and partition data of various solutes, the partition systems and the relevant parameters need to be defined. In the static equilibrium experiments, the notation, solvent (C°)/gel (Cg), refers to the transfer of a solute from the static solvent phase to the gel phase, C° and Cg indicating the molar equilibrium concentrations of the solute in the two phases. When the equilibrium experiment is performed at the saturation of the solute, C° and Cg refer to the solubilities in the external solvent and in the gel phase, respectively. In the gel chromatographic system, mobile phase (C jj)/ gel (Cg, Kgy) refers to the transfer of a solute from the mobile phase to the gel phase, C and Cg indicating the equilibrium molar concentrations of the solute in the two phases, which are correlated each other by Cg/Cuj = The notation, mobile phase (Cjjj)/gel (C°, K° )i applies to the ideal chromatographic transfer process where the distribution coefficient (K° ) Is determined solely by the steric exclusion effect of the gel matrices without any differential interactions of the solute with the two phases. The experimental determination of is subject to some uncertainty as it is difficult to establish such an ideal condition. By inclusion of urea (ref. 40,41,73) and methanol (ref. 41) in the eluents effects other than the purely steric can largely be eliminated, but there is no direct method to confirm the absence of additional gel-solute interactions. This will be further examined later. All the transfer parameters given below are the apparent quantities evaluated using the observed molar concentration data. 

Since = Cg/C , AF , can also be regarded as the transfer free energy 

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