Development, characterization and application of restricted-access media for high-performance liquid chromatography
Abstract
The purpose of the research is to develope and characterize reversed-phase restricted-access high-performance liquid chromatographic (HPLC) packings which allow retention of small, hydrophobic drugs while excluding proteins. This is achieved by creating a size-discriminating barrier in the packings such that large molecules are restricted from access to adsorptive chromatographic surfaces, while small molecules are free to pass the barrier and contact the surfaces for partitioning. Such HPLC materials can be useful in therapeutic drug monitoring (TDM) because they allow direct injection of biological samples. Thus, time-consuming sample preparation procedures can be eliminated. Two different types of restricted-access media for liquid chromatography are examined in this dissertation. The first, internal-surface reversed-phase (ISRP) packing, was developed previously and is based on differentiation of internal and external surfaces in porous packing particles. The second type is based on size-selective permeability of surface coatings and is called semipermeable-surface packing. Physical, chromatographic and chemical characterizations of ISRP packings, produced from various small-pore silica supports, were performed in order to elucidate the effects of physical properties on chromatographic performance. The application of semipermeable-surface technology to HPLC separations is demonstrated through development and characterization of a poly(vinyl alcohol)-coated octadecylsilyl packing, and through an automated column-switching analysis of antidepressant drugs in serum that is based on sample cleanup with a diol-phase silica column. In addition, a poly(styrene-divinylbenzene) HPLC support was modified with a crosslinkable dodecyl-polyglycidol ether (DPGE) surfactant to produce a stable hydrophilic surface coating potentially suitable for bioseparations.
Degree
Ph.D.
Advisors
Pinkerton, Purdue University.
Subject Area
Analytical chemistry
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.