CONCURRENT SOLUTION AND ADSORPTION PHENOMENA IN CHROMATOGRAPHY .I. GENERAL CONSIDERATIONS

The dependence of the several sources of solute retention in chromatography - bulk liquid partition, liquid interfacial adsorption, and solid support adsorption - on solvent volume and on surface areas is considered for a variety of practical situations. The relative magnitudes of the individual contributions may then be qualitatively predicted over a wide range of stationary phase loadings, for the situations of (a) constant sample size and (b) constant concentration of solute in the mobile phase. The individual contributions are finally summed to show qualitatively the various forms of variation of the net retention volume with liquid loading which may be met with in practice. The results are presented in graphical form. Certain features are found in these curves which are useful for diagnosis of interfacial adsorption effects in chromatography. The predicted curves are in formal agreement with published experimental plots. Means for the recognition of and correction for interfacial adsorption effects in experimental data are suggested. For chromatographic systems in which all three mechanisms occur, only bulk liquid partition coefficients can be determined unequivocally by chromatography alone. The range of application of chromatography to the measurement of physicochemical data is considerably broadened by these conclusions.