Sep-Pak Alumina B Plus Long cartridges contain a highly active grade of alumina with a basic surface chemistry. The aluminum oxide surface provides an extremely polar surface for analyte retention and has properties of a Lewis acid. This normal phase sorbent is similar in use to silica; however, it is slightly more stable than unfunctionalized silica under high pH conditions. This basic alumina is also low-capacity ion exchanger in aqueous media. Sep-Pak Alumina B Vac cartridges can be used to extract phospholipids, steroids, and catecholamines. Since Sep-Pak Alumina B is unaffected by high-energy radioactivity, these cartridges can be used for radioactive compound isolation. These versatile cartridges can attach easily to pumps and syringes for reliable, positive-pressure flow to speed up the sample processing time. They can also be fitted with removable reservoirs and used on vacuum-assisted flow devices and certain automated systems.