Printable Meeting FlierJanuary Meeting Notice
Tuesday, January 15, 2008
Shape Selective Stationary Phases: Design, Synthesis, and Characterization
Dr. Kate Rimmer
National Institute of Standards and Technology (NIST)
Gaithersburg, MD
Abstract:
Alkyl modified silica surfaces are the most commonly used and studied bonded phases in liquid chromatography. The chromatographic effects of phase length, ligand density, and column temperature have been investigated extensively and it has been found that longer alkyl chains, higher densities, and lower temperatures typically lead to improved separations of shape constrained geometric isomers such as polycyclic aromatic hydrocarbons and carotenoids. Infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and molecular dynamic simulations have been used to characterize a range of phases. Combined with chromatographic separations these data produce a compelling picture of the stationary phase morphology indicating that ordered alkyl ligands give rise to shape selectivity.
Perfluorinated alkyl modified silicas are emerging as potentially important stationary phases in reversed-phase liquid chromatography (RPLC). It is anticipated that fluorinated ligands may be more rigid and may provide enhanced shape selectivity as well as unique retention of polar solutes. Fluorinated C8 alkyl phases yielded atypical solvation effects and retention, however there was no evidence of shape selectivity. A novel long chain fluorinated phase was synthesized through the linkage of a perfluorinated acid to modified silica particles. In addition to the atypical solvation effects, this phase showed unique shape selective characteristics at much higher temperatures and lower ligand densities than traditional hydrocarbon phases.
About the Speaker:
Kate Rimmer received her B.A. degree at the University of Vermont in chemistry & anthropology. After receiving her degree, she worked for Wyeth Ayerst for 3 years. She then decided to attend graduate school and obtained her Ph.D. in analytical chemistry from Florida State University where she investigated electrochromatography under the direction of John Dorsey. She completed a National Research Council postdoctoral fellowship at the National Institute of Standards and Technology (NIST) where she worked on the synthesis and characterization of stationary phases for liquid chromatography. Kate remained at NIST as a research chemist where she continues her stationary phase research and uses her expertise in liquid phase separations to expand dietary supplement measurement capabilities. She is the coordinator for the NIST/NIH Dietary Supplement Quality Assurance Program. She has served as President, Program Chair and is currently on the Executive Board of the Washington Chromatography Discussion Group.
Details:
| Location: | D'ignazio's Towne House |
| Times: | 5:00 PM Executive Committee Meeting 5:45 PM Social "Hour" 6:30 PM Dinner 7:30 PM Presentation |
| Cost: | $30 |
| Dinner Choices: | Chicken Parmesan & Spaghetti Baked Tilapia (fish) Eggplant Parmesan |
NOTICE TO STUDENTS AND FACULTY: Full-time students with valid ID may attend dinner meetings at half-price. Faculty members at colleges and universities are urged to bring one or more students to the meeting. If they do, they also can attend at half-price.