Hydrogen bonding : XV. A new characterisation of the McReynolds 77-stationary phase set

The following equation has been applied to all the phases in the McReynolds 77-stationary phase set. ▪ In this equation, V 0 G is the specific retention volume for a series of solutes on a given stationary phase, and the explanatory variables are R 2 a modified solute molar refraction, π * 2 the solute dipolarity, α H 2 the solute hydrogen-bond acidity, β H 2 the solute hydrogen-bond basicity, and log L 16 where L 16 is the solute Ostwald absorption coefficient on hexadecane at 25°c. The constants in the equation are obtained by multiple linear regression analysis, using about 150 data points in eacy regression, and values of r, s, a, b and l are regarded as characteristic constants of the phases that serve to classify the 77-phase set. It is shown that the classification of the phases into clusters is in accord with chemical principles, and is in excellent agreement with previous work using hierarchical clustering, minimum spanning tree techniques, and pattern cognition methods. The above equation allows the factors that lead to gas-liquid chromatographic separations to be identified, and provides quantitative information on the various solute-solvent interactions that give rise to these factors.