In gel filtration, large molecules elute:
Gel filtration, also called size exclusion chromatography, uses porous beads with defined pore size. Separation is based on accessibility to internal pore volume. Large molecules exceeding pore diameter cannot enter beads and are limited to interstitial void volume, traveling fastest. Smaller molecules permeate pores, experiencing larger accessible volume and longer path. Consequently, large molecules elute first, followed by intermediate and small molecules. This inverse size-elution relationship allows desalting, molecular weight estimation, and protein oligomer purification without adsorption. Column calibration with standards enables determination of approximate molecular mass based on elution volume.
Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.