Abstract: Prospects for using synthetic and modified nanostructured mesoporous adsorbents for the adsorption, preconcentration determination, and chromatographic separation of biologically active substances (BAS) are shown. The need in the account of the effect of the structure of nanocomposites on their adsorption capacity is noted. The structuredness of mesoporous materials such as MCM-41 and the high rate of delivery and removal of biologically active substances (adsorption–desorption) upon contact with the material increase the efficiency of chromatographic columns. Procedures for the preconcentration and separation of phospholipids on silicon-containing materials, such as MCM-41, are developed. The number of stages in the isolation, preconcentration, and determination of BAS was decreased by increasing the recovery of the target component by ordered composites based on MCM-41. Dynamic preconcentration of phosphatidylcholine on mesoporous adsorbents is described using the dynamic model for convex adsorption isotherms. An increased efficiency of adsorption preconcentration on nanostructured adsorbents is achieved through the more complete use of the adsorption capacity while reducing the loss of the analyte under dynamic conditions. © 2018, Pleiades Publishing, Ltd.