Studies On Preparation By Encapsulated Copolymerization And Usage Of Silica-based Packings In High Performance Liquid Chromatography

The silica based stationary phases are widely used in high performance liquid chromatography (HPLC). The silanized bonded phases usually have fine chromatographic behavior and selectivity. But the many residual silanol groups, which usually cause irreversible adsorption of solutes, especial basic solutes, lead to tailing and even disappearance of chromatographic peaks. These bonding phases are also limited by the narrow pH range in which they can be used. They are very unstable in basic media. Encapsulated phases have recently been developed to overcome these shortcomings. They are prepared by coating polymer on to the silica surface to give an uniform organic film. Column packings prepared in this way have both good chromatographic behavior and superior selectivity. Direct contact of the silica matrix with the mobile phase is avoided due to the coated organic film. So such phases can be used in basic media, the conditions demanded for the separation and analysis of biological active species and medicament. The life span of column is lengthened, and the cost is decreased as well. Due to these advantages, the encapsulated stationary phase becomes a kind of rapidly developing one in HPLC.