Great improvement of chromatographic performance using MCM-41 spheres as stationary phase in HPLC

Grafted MCM-41 materials are ordered mesoporous adsorbents suitable For reversed-phase liquid chromatography applications (RP-HPLC): they possess high surface area, which is a great advantage to enhance the thermodynamic behavior of the classical stationary phase by increasing solute retention. Hence, MCM-41s allow the separation of poorly retained solutes which are hard to separate on conventional silica gels. Furthermore, the ordered porosity in MCM-41 enhances the kinetic properties of the classical stationary phase. MCM-41s afford higher and more homogeneous molecular diffusivity, which increases the column efficiency for high flow rates as compared to that of classical silica-based columns. Besides, RP-HPLC provides a meaningful description of the particle size distribution at a macroscopic scale and of the pore ordering by probing the diffusivity of solutes. MCM-41s obtained by pseudomorphic synthesis of silica gel have successfully passed all the chromatographic tests and the results show that this new synthesis pathway really allows independent control of the pore size and the particle size of MCM-41. Spherical particles of 5 mum of MCM-41 without aggregation have been synthesized by this route and are revealed as very good candidates for stationary phases in RP-HPLC.