Contributions to the theory of chromatography

Abstract

A complete analysis has been given of the process of chromatographic separation for two solutes, the adsorption of which follows a Langmuir isotherm. Development of the bands, both with pure solvent and with a solvent containing another solute, has been discussed. Very simple conditions were found to hold for both the volume of solvent and the amount of adsorbent required for complete separation of the two solutes. Provided that the concentrations used are not too low-which is unfavourable-the influence of the initial concentrations is very small. For substances difficult to separate, the minimum amount of adsorbent X$_{0}$ (in g.) is proportional to the quantities to be separated (m$_{1}$ + m$_{2}$) (in mol.), and inversely to the saturation capacity of the adsorbent (1/$\beta $) (in mol./g. adsorbent) and to the square of the relative difference of the adsorption coefficients (a$_{1}$ and a$_{2}$) of the solutes X$_{0}$ = approximately $\beta $(m$_{1}$ + m$_{2}$)/(a$_{2}$/a$_{1}$ - 1)$^{2}$. The accurate equations are given in the paper.