Kenneth W. Busch

B.S. Florida Atlantic University, 1966;
Ph.D. Florida State University, 1971;
Postdoctoral Fellow, Cornell University, 1972-1974;
Visiting appointments-California Institute of Technology, Cornell University;
Appointed to faculty 1974.

Analytical Chemistry

Research in analytical chemistry provides new measurement technology needed for advances in modern high technology. Because the ability to characterize complex materials with regard to composition and purity is the foundation of modern high technology, demand for analytical chemists with advanced degrees is high. Research in the analytical spectroscopy laboratory is directed jointly by Profs. Kenneth and Marianna Busch, and deals with analytical spectroscopy in the broadest sense.

For the past few years, this research has focused on the application of chemometrics to problems in analytical spectroscopy. Most recently, our research group has been particularly interested in studying new potential spectroscopic methods of chiral analysis. The need for improved strategies for the determination of enantiomeric composition arises from increased pressure on the pharmaceutical industry by government agencies for documentation on the pharmacological effects of single-enantiomer drugs combined with the simultaneous demand in drug development for the determination of enantiomeric excess in large combinatorial libraries. While many techniques for chiral analysis have been developed over the years, gas- and liquid chromagraphy, capillary electrophoresis, and nuclear magnetic resonance are currently the most widely used. For high-throughput screening, separation methods are relatively slow and rapid spectroscopic techniques are most desirable.

Experimental discrimination of enantiomers is carried out conventionally by means of chiral auxiliary agents such as chiral shift reagents (in NMR), chiral complexing agents (in chromatography), and chiral solvents. This enantiomeric discrimination arises when a given enantiomer of the chiral auxiliary interacts with two enantiomers of a chiral analyte to produce diastereomeric pairs with different physical properties. Cyclodextrins are barrel-shaped sugar molecules that can form transient, non-covalent diastereomeric guest-host complexes with chiral guest molecules. Because the complexes that are formed are diastereomeric, they have different physical and spectral properties.

Recent research in our laboratories has shown that small spectral differences can be observed in the electronic spectra of solutions containing cyclodextrins and a chiral analyte as the enantiomeric composition of the chiral analyte is varied. While these small spectral variations might easily be dismissed as having little analytical utility, we have found that modern methods of multivariate regression analysis provide powerful data reduction strategies for making use of this information. Our research has revealed that good regression models can be prepared that can predict the enantiomeric composition of unknown samples of chiral analytes with a prediction accuracy of ¦ 5%. At the present time, we are actively studying various other potential chiral auxiliary agents (such as modified cyclodextrins) in an effort to improve the enantiomeric discrimination of the technique. In addition to supramolecular guest-host chemistry, this research involves a variety of spectroscopic techniques, as well as the application of chemometrics to spectroscopic data.

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1 (a) Kenneth W. Busch, Isabel Maya Swamidoss, Sayo O. Fakayode, and Marianna A. Busch, "Determination of the Enantiomeric Composition of Guest Molecules by Chemometric Analysis of the UV-Visible Spectra of Cyclodextrin Guest-Host Complexes," J. Am. Chem. Soc., 2003, 125, 1690-1691; (b) Kenneth W. Busch, Isabel Maya Swamidoss, Sayo O. Fakayode, and Marianna A. Busch, "Determination of the Enantiomeric Composition of some Molecules of Pharmaceutical Interest by Chemometric Analysis of the UV Spectra of Cyclodextrin Guest-Host Complexes," Anal. Chim. Acta, 2004, 525, 53-62; (c) Sayo O. Fakayode, Isabel M. Swamidoss, Marianna A. Busch, and Kenneth W. Busch, "Determination of the Enantiomeric Composition of some Molecules of Pharmaceutical Interest by Chemometric Analysis of the UV Spectra of Guest-Host Complexes Formed with Modified Cyclodextrins," Talanta, in press; (d) Sayo O. Fakayode, Marianna A. Busch, and Kenneth W. Busch, "Determination of the Enantiomeric Composition of Phenylalanine Samples by Chemometric Analysis of the Fluorescence Spectra of Cyclodextrin Guest-Host Complexes," The Analyst, in press.

Contact

Phone: (254) 710-6870
Email: Kenneth_Busch@baylor.edu