METHOD OF CHROMATOGRAPHIC DETERMINATION OF EXCESS ADSORPTION FROM BINARY-LIQUID MIXTURES

Excess adsorption isotherms determined by the chromatographic method were shown to be highly reproducible. The principle of the method is to use the adsorbent as column packing and the binary mixture as eluent and to determine in this system retention data of labeled components of the binary mixture. Adsorption points were calculated from retention data of deuterium-labeled components of an acetonitrile/water binary mixture by using silica gel as column packing chemically modified with a dense triorganylsilyl graft. Deuterium oxide can readily exchange its deuteron across the graft with protons of unreacted silanols under the graft. The necessary relationships have been derived to correct retentions for H/D exchange, and the results were applied for the evaluation of retention data. Finally, it was shown that the resulting excess adsorption isotherms could be described sectionwise by third-order polynomials by using the cubic B-spline. © 1990, American Chemical Society. All rights reserved.