Analytical Chemistry

Phone: 502-852-7061
mcyappert@louisville.edu

One of our research themes is the development and application of spectrochemical analytical approaches for the selective determination and quantitation of species in complex matrices, particularly those of biological interest. As an example, we are applying laser induced fluorescence, UV-visible absorption, Fourier transform infrared, and more recently NMR spectroscopies to study, at the molecular level, processes which may lead to the formation of cataracts in human lenses. Fiber optical sensors have been used in conjunction with laser induced fluorescence to map the distribution of extrinsic fluorophores in human lenses. Changes in protein secondary structure are being investigated by monitoring the conformation-sensitive Amide I band region of the infrared spectrum. This broad band is the result of the overlap of bands corresponding to each structural component, i.e., {alpha}-helix, {beta}-sheet, {beta} turns and random coil. The resolution of these bands is achieved by applying computa-tional procedures, such as derivative spectroscopy and the nonlinear adaptation of the Kalman filter.

The theoretical and experimental characterization of fiber optical sensors is another area of our research. These studies allow us to design more sensitive sensors and to control the size and location of the interrogated sample volumes. This type of information is particularly relevant in the application of optical sensors to biological samples that are not homogeneous and can be affected by the presence of the sensing device.

Besides the above areas of research, my students are actively involved in the development of instrumental accessories, and interface hardware and software. We interact very closely with the faculty in the Department of Ophthalmology. Separation procedures and biological assays necessary in our studies are often performed in the Department of Ophthalmology under the supervision of Dr. Douglas Borchman, who has collaborated with us since 1987.
 

Sphingolipids in human lens membranes: an update on their composition and possible biological implications
M. Cecilia Yappert and Douglas Borchman
Chem. Phys. Lipids 2004, 129, 1-20

Alternative approaches for the detection of various phospholipid classes by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry
Rosendo Estrada and M. Cecilia Yappert
J. Mass Spectrom. 2004, 39, 412-422

In situ MALDI-TOF MS regional analysis of neutral phospholipids in lens tissue
Madalina Rujoi, Rosendo Estrada and M. Cecilia Yappert
Anal. Chem. 2004, 76, 1657-1663

Glycero- versus sphingo-phospholipids: correlations with human and non-human mammalian lens growth
M. Cecilia Yappert, Madalina Rujoi, Douglas Borchman, Igor Vorobyov and Rosendo Estrada
Exp. Eye Res. 2003, 76, 725-734

Effect of sphingomyelin versus dipalmitoylphosphatidylcholine on the extent of lipid oxidation
Elena M. Oborina and M. Cecilia Yappert
Chem. Phys. Lipids 203, 123, 223-232 (2003)

Light scattering of human lens vesicles in vitro
Daxin Tang, Douglas Borchman, Arne K. Schwarz, Marta C. Yappert, G. F. J. M. Vrensen, J. van Marle and Donald B. DuPre
Exp. Eye Res. 2003, 76, 605-612