Expanded solubility parameter treatment for classification and use of chromatographic solvents and adsorbents

Abstract

The application of an expanded solubility parameter treatment in terms of interaction forces to various chromatographic processes is examined. Estimation of selectivity and classification of phase systems is possible with this approach. The general scheme is developed by relating the model to the processes of vaporization, solution, mixing, and adsorption. The scheme is first applied to gas-liquid chromatography. The Rohrschneider empirical approach for classification of stationary liquid phases is derived in terms of the present treatment. The validity of the model is shown with experimental data on a series of moderately polar stationary liquid phases. Gas-solid chromatography is next examined where it is shown that induction forces can be neglected in the adsorption process. These results are then applied in liquid-solid chromatography, where solvent strength with graphitized carbon black as adsorbent is shown to be proportional to the dispersion solubility parameter of the solvent. Solvent strength on polar adsorbents is next correlated with the polar solubility parameters of the solvent. Functional group adsorption strengths are shown to be proportional to the polar solubility parameters of the groups. Finally, the application of the model to liquid-liquid chromatography is briefly discussed, and the limitations in aqueous solutions are noted.

Adsorption Models

“…[10]). Many classification schemes have been proposed for organic compounds, but one scheme has emerged that has a thermodynamic basis and wide applicability [11,12,13]. The total solubility parameter (d T ) is defined as the cohesive energy density of a compound in the pure state.…”

Properties of materials as determined by inverse gas chromatography

“…Determination of the solubility parameter for solid materials by means of inverse gas chromatography is based on the model of adsorption described by Snyder and Karger and requires the knowledge of adsorption energy value (19) for the respective test solutes [46][47][48].…”

Limiting activity coefficients in dilute solutions of nonelectrolytes. II. Determination for polar–nonpolar and polar–polar binary mixtures, and the application of some solubility-parameter treatments

“…The data may also be used for testing extended solubility-parameter models. In the present paper three such extended-solution treatments (3)(4)(5)(6)(7)(8) are considered. In addition, the degree of constancy of the ratio of the dipole -induced dipole interaction parameters of a solute in two given solvents, first reported by Milanova and Cave (I), was tested.…”