John Dorsey's
Research Interests

Fundamental and Applied Separation and Flow Analysis

Our research interests lie in the areas of both fundamental and applied separation and flow analysis, including liquid chromatography, capillary electrophoresis and flow injection analysis. Separation techniques are the "necessary evils" for most real analysis, as most samples are far too complex to be analyzed by a direct method. The basic thesis underlying our research efforts is to better understand the chemistry of the separation process, and use that understanding for the solution of practical problems facing practicing analytical chemists. The understanding of the chemistry of the separation process also allows the chromatographic process to be used to acquire other important physico-chemical partitioning data.

Prediction of Retention in Reversed Phase Liquid Chromatography

One long range goal is the development of a sound, fundamental theoretical basis for prediction of retention in reversed phase liquid chromatography. This is a combined experimental and theoretical effort in collaboration with Professor Ken Dill of the University of California, San Francisco, and Professor Tom Bech of the University of Cincinnati. We are measuring partitioning of small molecules between carefully characterized stationary phases, which we synthesize, and traditional mobile phases. These measurements are providing advances in theory and in practice, through improvements in separational selectivity, gradient elution schemes and reproducibility of stationary phase materials.

Open Tubular Capillary Electrophoresis (CE)

Open tubular capillary electrophoresis (CE) is a relatively new technique in which solute species are separated in narrow-bore capillaries, typically 50-100 m inside diameter, based on their differential rates of migration under an applied electric field. CED enjoys a significant advantage over liquid chromatography due to the extremely high resolution which results from very limited zone broadening as a result of electrophoretic "plug" flow versus hydrodynamic "laminar" flow. For example, efficiencies of greater than a million theoretical plates have been reported for CE, versus typical efficiencies of approximately 10,000 plates for reversed phase LC. There is still much that is not understood about the chemistry of the separation process in CE. The chemistry of the capillary walls, the use of organized media (including "gels"), and the extraction of other partitioning information are all of current interest.