Christine L. Copper
Ph.D., University of Tennessee
U.S. Naval Academy 572M Holloway Road
Annapolis, MD 21402-5026
Professor Copper focuses on development of separation and detection methods applicable to forensic analysis. Specifically, capillary electrophoretic and micellar electrokinetic capillary chromatographic separation methods are being developed to study dyes, inks, explosive residues, and other molecules of interest to forensic scientists.
General Overview of Capillary Electrophoresis and Micellar Electrokinetic Capillary Chromatography:
Chemical separations are essential to many areas of science. Some example uses of chemical separations include detection of illegal drug use by individuals, purification of medications, analysis of foods for the presence of harmful pesticides, or determination of the amount of caffeine in coffee, and types of dyes in fabric.
Chemical species are separated in capillary electrophoresis (CE) by placing the sample to be analyzed into a small (inner diameter of 50 mm) glass capillary tube which contains a buffer solution and applying a high (20-30 kV) voltage across the ~50 cm length of the capillary. The field that is applied causes different chemical species to travel at different rates, according to their charge and size, through the capillary towards a detection system. Micellar Electrokinetic Capillary Chromatography (MEKC) is a variant of CE which has micelles added to the buffer solution in the capillary. The micelles are spherically shaped aggregates of surfactant molecules that are charged on the outside but have a nonpolar center. Sample molecules will partition into the micelles based on their polarity thus the micelles act like a pseudo-stationary phase and allow neutral molecules to be separated.
Various detection systems are used in CE or MEKC experiments. The most common systems are those that shine light from an ultraviolet lamp or a laser through the glass column or channels. Depending on the chemical species, this light is either be absorbed or causes the species to emit light of a different wavelength. Either of these events are easily seen using detection equipment such as a photomultiplier tube.
Applications of Capillary Electrophoresis and Micellar Electrokinetic Capillary Chromatography:
Professor Copper has published articles reporting the use of CE and MEKC to analyze chemical warfare agents, explosives, dyes from fabrics, dyes in inks, carbon monoxide in blood, and poisons in drinks. She and her students continue to develop CE or MEKC methods of analysis for other "real world" systems.