RANDOM WALK SIMULATIONS OF MASS TRANSPORT IN COMPLEX CHROMATOGRAPHIC MATERIALS

Mark SchureChromatographic techniques play a central role in separation science for a wide range of elds. The manufacture and use of devices that operate on the nanoscale as well as porous-layer open-tube (PLOT) systems are becoming more prevalent due to their potential to provide more e cient separations. This thesis attempts to model mass transport phenomena in these systems through simulations utilizing random-walk techniques. The simulations model the ow of nite tracer particles through porous and nonporous capillary systems at varying time and length scales. First, the e ect of uid slip, or a nonzero velocity, at walls is investigated. The impact of retention on the e ects of slip ow is considered, and it is determined that the use of slip ow is limited in application but can provide improved e ciency to certain nanoscale systems. Next, PLOT systems are modeled as a central capillary with radially-oriented cylindrical pores. Pore and solute sizes are varied to gain insight into how these variables e ect elution times from the capillary. The simulations provide the capability to calculate mass transport rates which would be otherwise impossible using experimental or ana- lytical methods. These ndings underscore the potential of a computer-aided approach for the design of improved analytical separation systems.Chemical Engineerin