Research

Our research focuses on unraveling the mechanics of separations and applying separation techniques in bioanalytical chemistry and environmental analysis. The thrust of the research effort is in two areas: physical-analytical separation science and analyte/ligand interaction studies. Our efforts in the former focus on optimization of flow dynamics and mass transfer events in separations systems. In the latter, we study affinity-type separations and harness molecular recognition processes to achieve high selectivity separations and obtain information about molecular interactions.

The tools and techniques we are developing include capillary electrokinetic chromatography (CEC), capillary gel electrophoresis (CGE), capillary zone electrophoresis (CZE), and packed capillary high performance liquid chromatography (HPLC). These techniques offer several distinct advantages over more conventional separations techniques - including increased efficiency, high selectivity, and high peak capacity - which are allowing for new inroads to be made in the analysis of trace compounds in complex biological, pharmacological, and environmental matrices.

Capillary electrokinetic chromatography is an emerging separation technique in which mobile phase is electroosmotically pumped in a packed capillary HPLC column. Electroosmotic drive presents an effective means of reducing regional flow velocity inhomogeneities in packed liquid chromatographic columns, thereby minimizing zone spreading, which yields high efficiency and peak capacity. We have achieved even further efficiency enhancements by demonstrating the feasibility of perfusive (through-particle) electroosmotic transport. CEC may be used in combination with many different mechanisms of separation, yielding a variety of selectivities. Examples would include reverse-phase CEC, size exclusion CEC, and affinity CEC.

Molecular recognition processes are also of great interest to us, and are typified by the biospecific interaction of a ligand in the separation medium with an analyte (such as an enzyme, immunoglobulin, nucleic acid, or pharmaceutical agent). The interaction of the ligand and analyte results in a change in the migration or elution behavior of the analyte, which leads to separation. Ligands may be biological receptors, enzyme substrates, etc. An alternative approach to achieving molecular recognition is the employment of molecular-imprinted-polymer technology, in which a chromatographic sorbent is custom produced by polymerization around a template molecule. This ultimately yields a molecular "fingerprint" which is capable of interacting in varying degrees with molecules which are structurally similar to the template. These materials have applications in library screening and chiral separations.

This page last modified: 31 January 2001