An innovative approach to separate amphiphilic biomolecules in a fixed bed adsorption experimental set-up is discussed and experimental results are presented. High hydrostatic pressure of up to 360 MPa is utilized to control the sorption equilibrium. Major advantages of this approach are that no auxiliary substances are required for the separation that have to be removed afterwards. Furthermore, of the two physical parameters pressure and temperature that can be used to control reaction or sorption equilibria, pressure is the less harmful one towards the activity of biomolecules. To realize this approach, interdisciplinary researches were necessary. The surfaces of different silica gels were chemically modified in order to synthesize adsorbents with the desired properties. Two high pressure devices were designed and built. One is an circulation plant to investigate equilibrium states. It was utilized to record adsorption isotherms under a pressure of up to 300 MPa. The second one is a semi-continuous set-up for a fixed bed reactor. It was hydrodynamically characterized and afterwards used to look into breakthrough curves and separation cycles. The adsorption capacity of the tailor made adsorbents and its pressure dependency was examined via these plants in equilibrium (isotherm) and dynamic (breakthrough) experiments. Therefore, the nonionic surfactant Triton X-100 was applied as a model substance for e.g. glycolipids, which are within the scope of the separation method. During these experiments a surface modification was identified that showed a high adsorption capacity under high pressure conditions. At the same time at ambient pressure, which represents the desorption condition, it had nearly none adsorption capacity. Furthermore, the adsorption isotherms (taken at room temperature) become more favourable with increasing pressure, indicating an increasing affinity towards the applied surfactant. Experimental data were analyzed utilizing the Langmuir, Frumkin, and Temkin isotherm models. It was found that the best fit could be achieved with the Temkin-type isotherm. The dynamic experiments matched the findings from the isotherms. With increasing pressure the breakthrough of the surfactant through the fixed bed arrangement occurred later. Full separation cycles including adsorption (breakthrough), washing, desorption, and regeneration proofed that the surfactant can be regained and hence the method is feasible. In the first step up to 75% of the initial concentration could be desorbed. The process was then optimized and it was found that there is an optimum pressure for the system examined. If the goal is to maximize the regained concentration, the best adsorption pressure is around 300 MPa. For an optimal efficiency, defined as amount of pressure desorbed substance in relation to unbound and removed compounds in the washing step, the adsorption pressure should be closer to 200 MPa. An influence of the utilized adsorbent's silica structure was discovered as well and a best pore size is suggested. (C) 2006 Elsevier B.V. All rights reserved.