Research Interests of Morteza G. Khaledi
Our research program includes both mechanistic studies and bioanalytical applications of High Performance Capillary Electrophoresis (HPCE) and High Performance Liquid Chromatography (HPLC). Several projects are either presently under study or will be initiated in the near future.
A new avenue of research includes investigations of the unique capabilities of HPCE techniques in solving bioanalytical problems. HPCE offers specific advantages to improve separation, detection sensitivity and selectivity, and speed for analysis of complex biological samples. Projects include development of sensitive methods with Laser Induced Fluorescence (LIF) detection for analysis of antisense substances and for monitoring gene delivery and expression in single biological cells.
The focus of another research area is characterization of solute interactions with organized media such as micelles, vesicles, ionic polymers, and other pseudo - stationary phases in Electrokinetic Chromatography (EKC). A better knowledge of solutes interactions with these pseudo-stationary phases is essential in improving separations. These projects include development of quantitative models known as Linear Solvation Energy Relationships (LSER) as well as spectroscopic probe studies for classification of the chemical selectivity of the pseudo - stationary phases in EKC. One study involves investigations of solute partitioning into membrane - mimetic pseudo phases by EKC. A combination of unique capabilities of EKC in physico - chemical studies and biomimicry of lipid bilayer pseudo - phases is advantageous in achieving a better understanding of solute permeability in biological cells.
Another area of interest is the applications of CE for the separation of enantiomeric isomers of pharmaceutically important molecules. Chiral separations can be achieved by CE through the inclusion of a proper chiral selector in the buffer solutions. Several projects are involved for achieving a better understanding of chiral recognition mechanisms and development of methodologies for the selection of proper chiral interactive media, and optimization of CE separations.
We are also investigating the usefulness of purely nonaqueous media in CE. Nearly all of the CE separations have been performed in aqueous media. Electrophoretic separations in purely nonaqueous solvents can broaden the range of applications of HPCE to hydrophobic solutes. In addition, selectivity of electrophoretic migration in organic solvents differs from that in water due to differences in solvation and acid - base chemistry. In addition to selectivity studies in nonaqueous media, other projects involving band broadening mechanisms, detection enhancement, and sample concentration are being pursued.
In another area, the goal is to develop effective and efficient methodologies for the rapid optimization of HPCE and HPLC separations. This is accomplished by identification of important parameters, derivation of quantitative descriptions of the migration behavior, and by development of computer - aided protocols for rapid optimization of parameters.
Finally, applications of Micellar Electrokinetic Chromatography (MEKC) and Micellar Liquid Chromatography (MLC) in Quantitative Structure Activity Relationships (QSAR) are being investigated. Using chemometric techniques, quantitative relationships between biological activity, chemical structure, and chromatographic retention are studied. These relationships are of great interest in a wide range of disciplines such as drug design, toxicology, and environmental fate studies.