Research Description - Michelle M. Bushey --last changed 5/10/07
General:
My current research interests are in the area of biological and biochemical applications of Analytical Chemistry; most specifically, capillary electrophoresis and capillary electrochromatography. The acquisition of a new instrument, aMALDI and ES interfaces to an ion trap MS will soon impact my research program.
Background:
Capillary Electrophoresis (CE) is a separation technique that has generated considerable interest in the analytical and biochemistry fields. CE separates analytes on the basis of electrophoretic mobility differences in an instrumental format. Extremely high separation efficiencies in the hundreds of thousands and millions of theoretical plates can be obtained in generally less than 20 minutes with automated and semi-automated equipment. The technique requires only small amounts of reagents and samples.
Micellar Electrokinetic Chromatography (MEKC) is a related technique and allows for the separation of
neutral compounds in an electric field. MEKC utilizes a micellar pseudo-stationary phase to obtain
separation of analytes. Analytes partition between the mobile buffer phase (usually aqueous) and the
pseudo-stationary micellar phase as they move through the capillary. The technique can be applied to the
separation of both charged and neutral analytes.
Capillary Electrochromatography (CEC) is a blending of liquid chromatography and capillary electrophoresis. The separation takes place in a capillary tube filled with a stationary phase. We are using porous polymer monoliths as the stationary phase. Transport through the column is the result of electroosmotic flow or a combination of electroosmotic and pressure driven flow. Separation can be based on partitioning alone or a combination of partitioning and electrophoresis.
Several
of the links listed on my 'links page'
have excellent descriptions of CE, some of these include animated cartoons.
One of our projects involves identifying the location of phosphorylation sites
in proteins. This is a collaborative project with Dr. Jon King of the Trinity
Biology department. HPLC, CE, CEC, and MS will all potentially be used to identify
specific sites of phosphorylation in our protein of interest.
A second interdisciplinary project with Dr. Jim Shinkle of the Trinity Biology department is concerned with the identification and possible quanitification of various plant flavonoids. We are interested in how the levels of the various flavonoids changes after plant exposure to UV light. HPLC, CE, CEC, MEKC, and MS will al potentially be used to identify and quantify these compounds.
Another project in the lab involves making porous polymer monoliths for use in capillary electrochromatography (CEC). A capillary is filled with a monomer solution and the polymerization process started. The polymer is formed in the capillary. We are studying the separation and physical properties of a variety of these polymers as well as their application to the separation of a variety of analytes, neutral, charged, small and large. These types of columns offer many advantages over conventional HPLC, and even over CE approaches. We are especially interested in their interface with mass spec instrumentation.
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