This research is in the general area of analytical and surface chemistry and in the subfield of separation science. This research involves the use of mass spectrometric tracer pulse chromatography (MSTPC) for the determination of phase distribution isotherms of a variety of relatively simple systems involving only one or two components and/or phases. Three major objectives are to be achieved in this research. These include 1) to investigate more complex systems for analysis by MSTPC, 2) the use of the acquired data for evaluation of current molecular solution and adsorption theories, and 3) development of a practical method for surface coverage programming in gas-solid chromatography. An experimental technique which uses stable isotope tracers in combination with mass spectrometry and chromatography to investigate molecular interactions has been developed and applied to a number of chromatographic systems. This technique will be used in this research to study the phase distribution at constant temperature for systems containing more than one component. These studies are designed to provide a better understanding and model for different chromatographic systems.