A process for chromatographic separation, comprising passing a sample through a chromatography apparatus to achieve separation of at least one component therefrom, wherein prior to the separation, a porous doped sol gel glass is included in chromatographic media in the apparatus, the doped sol gel glass being formed from a metal alkoxide by a gelling step conducted at room temperature and a drying step conducted at not greater than 41.degree. C., and the doped sol-gel glass containing a compound encapsulated therein which effects a pretreatment cleanup for interference removal.