Measurement of adsorption isotherms by liquid chromatography

Adsorption behavior on silica-bound hydrocarbonaceous sorbents used in high-performance liquid chromatography was investigated by frontal chromatography and elution on a plateau, and procedures were developed for data collection, analysis and correlation. Isotherms of selected compounds were measured, including several of biological relevance. The relative merits of various dynamic methods of isotherm measurement were compared and illustrated by experimental findings. The frontal analysis technique was determined to be more accurate and convenient than other methods. A miniaturized liquid chromatographic system was constructed to measure isotherms with milligram quantities of material by frontal development. The performance of this apparatus compared favorably with that of equipment which has dimensions usual in high-performance liquid chromatography and requires orders of magnitude greater amounts of a substance for isotherm measurement. Thus the miniaturized system is eminently suited for applications when the substance of interest is in short supply, as is the case with many biological substances. The effects of operating parameters on adsorption behavior were investigated, both to optimize the procedure, and to further explore the fundamental of the process.