Capcell Pak columns, manufactured by Shiseido Co., Ltd., Japan, distributed worldwide by Phenomenex, are durable, reproducible columns designed to eliminate secondary retention effects that lead to tailing peaks. A two-step synthesis is used: 1) surface coating of the base silica gel using a reinforced silicone polymer by vapor deposition, resulting in a homogenous monolayer, and 2) bonding of alkyl groups to the coated surface to shield any acidic silanols. This process provides excellent peak shape for acidic, basic and chelating compounds.