Chromolith® Prep monolithic stationary phases are new ultrapure silica phases which gain their special properties from a bimodal pore structure. This structure is a property of the new 'Sol-Gel' technology and consists of macropores and mesopores. The mesopores with an average diameter of 12 nm, form the fine porous structure of the column interior and create a very large surface area on which adsorption of the target compounds occurs.

The large macropores, with a pore diameter ranging from 3 µm, form a dense network of pores and allow a high flow rate due to a low resistance factor. The resulting excellent accessibility of the mesopores (total porosity >80%) ensures fast adsorption and desorption kinetics because of the short diffusion length inside the pores. This results in dramatically reduced separation times and thus greatly increased productivity.

To operate a monolithic column it is necessary to ensure that no flow through occurs in the wall region. Therefore the monolith is cladded with a polymeric material (special PEEK) and can be connected directly to each HPLC system and used as 'ready to use' column.