Sephadex is a gel filtration resin prepared by crosslinking dextran with epichlorohydrin. Different types of Sephadex differ in their degree of cross-linking and hence in their degree of swelling and their molecular fractionation range. Sephadex G-50 is one of five different G-types ranging from G-10 for small molecules to G-75 for larger molecules. Sephadex G-50 is available in 4 different particle sizes (Coarse, Medium, Fine & Superfine) and Superfine has the smallest bead size for higher efficiency with shorter diffusion distances. Coarse and Medium are are preferred for large scale group separations at where high flow rates and low operating pressures are required.