The concept of size-based separations by chromatography was first speculated by Synge and Tiselius,[ based on the observation that small molecules could be excluded from the small pores of zeolites as a function of their molecular size.The term “molecular sieve,” coined by J. W. McBain to describe this property of zeolites, was subsequently used to describe the technique commonly known today as size-exclusion chromatography. Over the years, SEC has been known by a number of other names, such as exclusion chromatography,teric-exclusion chromatography, restricted-diffusion chromatography, liquid-exclusion chromatography,gel-filtration chromatography, and gel-permeation chromatography. The first examples of size-based separations by liquid chromatography were noted by Wheaton and Baumanin their work on ion-exclusion chromatography. They observed that various nonionic species