講演者：Prof. Taihyun Chang
所属：Division of Advanced Materials Science and Department of Chemistry, Pohang University of Science and Technology (POSTECH)
題目：Changing Modes of Macromolecular Characterization: From Size Exclusion to Temperature Gradient Interaction Chromatography
Liquid chromatography (LC) has been extant for the characterization of natural and synthetic macromolecules for many decades. Main task is to probe heterogeneous mixtures in molecular weight, molecular architecture as well as in chemical composition. Among numerous variations of the LC technique, the size exclusion chromatography (SEC) has been most widely used for the analysis of molecular weight distribution of synthetic polymers. SEC separates the polymer molecules according to the size of polymer molecules in an eluting solvent. Thus, SEC is often inefficient in the separation of copolymers, polymer mixtures, branched polymers, polymers with different stereoregularity or end-group difference, and so on. Furthermore, the resolution of SEC is limited by the band-broadening problem.
In contrast, the interaction chromatography (IC) utilizes mainly the enthalpic interactions, adsorption or partition of solute molecules to the stationary phase, thus IC can be used efficiently for the applications where SEC fails. Furthermore, the band broadening is far less serious in IC than SEC, thus IC shows far better resolution than SEC. In this talk, IC methods for the characterization of polymers will be discussed with emphasis on the temperature gradient interaction chromatography (TGIC) that we have developed some years ago. In TGIC the column temperature is varied during the elution in a pre-programmed manner to control the solute retention. The hyphenation of IC with other chromatography techniques and/or mass spectrometry makes the separation technique much more powerful.