Current Meetings

September 2010 Meeting

"Molecular Interactions Contributing to Alternative Retention and Selectivity Using Fluorinated Stationary Phases".

The September 2010 CSSC meeting will be held at the Four Points by Sheraton Meriden, Meriden CT.  The meeting will feature a technical presentation by Dr. David S. Bell , Manager, Analytical Research and Services, Sigma-Aldrich/Supelco, as well as dinner. The cost of the meeting is $30 ($15 Students and Emeritus) and is to be paid at the event.

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Abstract:  

The use of fluorinated stationary phases in liquid chromatography and hyphenated techniques has become significant in recent years. Early applications in the effective separation of paclitaxel provided such phases much notoriety, however more recent studies focusing on orthogonality to traditional alkyl phases has invited even broader attention. Due to alternative retention mechanisms, fluorinated stationary phases often are employed for the retention and selectivity not provided by alkyl phases. Applications in arenas such as biopharmaceutical, pharmaceutical, natural product and environmental analyses are increasingly being reported.

Fluorinated, silica-based stationary phases have shown unique retention for small, polar analytes. In particular, pentafluorophenylpropyl (PFPP) phases exhibit both reversed-phase and normal-phase (HILIC) retention for polar analytes, which has shown to be dependent on mobile phase composition. At lower percentages of organic modifier, solute retention resembles that of classical reversed-phase systems. At higher percentages of organic, however, behavior more typical of normal-phase separations is observed with increasing proportions of organic modifier. Recent studies in the aqueous normal-phase region have indicated a considerable contribution of ion-exchange to retention and selectivity; a mechanism particularly useful for the separation of basic analytes.

A second important attribute of the fluorinated phases lies in their apparent increased shape selectivity relative to more common stationary phase chemistries. Fluorinated phases, therefore, are often superior to their alkyl counterparts for the separation of closely related compounds.

In order to effectively utilize this interesting and useful tool, it is important to have a basic understanding of the underlying mechanisms that govern retention and selectivity as well as a general sense of the structural moieties most suitable for it. This presentation will focus on several fundamental studies aimed at elucidating the dominant retention mechanisms contributing to observed alternative selectivity. Several examples from recent literature as well as the author’s laboratory will be highlighted.

Biography:

With a B.S. degree from SUNY Plattsburgh and a Ph.D. in Analytical Chemistry from The Pennsylvania State University, Dave spent the first decade of his career within the pharmaceutical industry performing analytical method development using various forms of chromatography and electrophoresis. During the past 15 years, working directly in the chromatography industry, Dave has focused his efforts on the design, development and application of stationary phases for use in HPLC and hyphenated techniques. In his current role of Analytical Research and Services Manager at Supelco, Dr. Bell’s main focus has been to research, publish and present on the topic of molecular interactions that contribute to retention and selectivity in an array of chromatographic processes.

Four Points by Sheraton Meriden
275 Research Parkway
Meriden, CT 06450

Last Updated:  08/31/2010 09:52 PM