COMPARISON OF RESOLVING POWER AND SEPARATION TIME IN THERMAL FIELD-FLOW FRACTIONATION, HYDRODYNAMIC CHROMATOGRAPHY, AND SIZE-EXCLUSION CHROMATOGRAPHY

In this study, a general framework is set up for a theoretical compari son of the capabilities of various methods for the separation of polym ers according to molecular mass. The resolving power and separation sp eed of thermal field-flow fractionation (TFFF), packed-column hydrodyn amic chromatography (PCHDC), open-tubular hydrodynamic chromatography (OTHDC), and size-exclusion chromatography (SEC) are evaluated, using well-established relations for retention and efficiency. Resolution is analyzed in terms of the underlying molecular mass selectivity and ef ficiency factors. For each technique, a dimensionless parameter is def ined including the basic variables affecting retention. Selectivity, e fficiency, and speed of separation are written as universal functions of this parameter, and optimum conditions are examined. The capabiliti es of the different methods under optimized working conditions are the n compared in terms of their ability to produce a desired resolution b etween two polymer fractions in the shortest possible time.