Correlation of the R_M-values of some heterocyclic bases, naphthols, naphthylamines and nitroanilines in adsorption and partition chromatography

Summary

The correlation between the R_M-values measured in both adsorption and partition chromatography have been investigated for a number of substances such as heterocyclic bases, naphthols, naphthylamines, and isomeric nitroanilines. Aluminium oxide G, silica gel G, and magnesium silicate were used as the adsorbent and formamide, ethylene glycol, and a pH=2.4 buffer as the liquid stationary phase. Eleven solvents served as the mobile phase. It was found that for all compounds investigated the function$R_{M_i } = f{\text{(}}R_{M_i }^p )$ is represented by a linear relationship corresponding to the equation$R_{M_i } = aR_{M_i }^p + b$. The constants a and b are characteristic for a compound in a given system of stationary phases (adsorbent and partitioning liquid).

The values of constant a in a given system for a group of compounds are close to each other and the differences are due to differences in the structure of the molecules. Changes in the values of b when changing the adsorbent or the partitioning liquid can be used under certain conditions to characterize the molecular interaction between the sample and the stationary phases.

It follows from these investigations that the linear correlation between the R_M-values measured in liquid adsorption and partition chromatography provides new possibilities in analysis as well as in physicochemical investigations.