Field Flow Fractionation (FFF): It’s Not Just for Large Molecules Anymore
Jeffrey Ahlgren
Senior Applications Scientist, Wyatt Technology
Light scattering comprises a versatile suite of non-invasive techniques for characterizing molecules and a wide range of particles in solution. In contrast to most methods for characterization, it does not require outside calibration standards. In this sense, it is an absolute measurement. Wyatt Technology’s instruments make two different types of light scattering measurements for absolute molecular characterization: Static Light Scattering and Dynamic Light Scattering. When combined with a separation technique like liquid chromatography, the molar mass and RMS radius are determined. While size exclusion chromatography (SEC) with MALS has been traditionally used for this analysis for many years, it is possible to use other chromatographic separation techniques such as Ion-Exchange Chromatography or Reverse Phase Chromatography in conjunction with MALS detection. Examples of these type of applications will be discussed. Dynamic Light scattering can be employed to determine the hydrodynamic radius of small as well as large molecules, and methods for batch as well as on-line DLS detection and analysis will be presented.
Jeffrey Ahlgren is a Senior Field Applications Scientist for the Southwestern Region for Wyatt Technology Corporation, based in San Diego, California. He has been with Wyatt Technology for more than 19 years, and is a former Dean and Instructor of their Light Scattering University training program. Prior to joining Wyatt Technology in 2002, he was a Research Chemist with the Agricultural Research Service of the USDA and was stationed at the National Center for Agricultural Utilization Research in Peoria, Illinois. His Ph.D is from the University of Illinois - Urbana Champaign, where he studied the antifreeze glycopeptides of Antarctic fishes