Practice question

The elution volume equation Ve = Vo + Kd*Vi describes size exclusion behavior. When measured elution volume equals void volume, Ve = Vo, substituting yields Kd = 0, indicating solute inaccessible to pore interior. This occurs for molecules larger than matrix exclusion limit, physically unable to enter beads due to steric hindrance. Such fully excluded species travel only through interstitial spaces and appear in earliest fractions. Fully included solutes equilibrate fully showing Ve = Vo+Vi. Partially included molecules exhibit intermediate volumes. Recognizing Ve=Vo as exclusion signature aids interpretation of chromatograms and selection of appropriate gel porosity.