Andualem Damtew Hamza Analysis of the potential of nonlinear solvent gradients in preparative chromatography Fakultät für Verfahrens- und Systemtechnik Otto-von-Guericke-Universität Magdeburg Analysis of the potential of nonlinear solvent gradients in preparative chromatography Dissertation zur Erlangung des akademischen Grades Doktoringenieur (Dr.-Ing.) von MSc. Andualem Damtew Hamza geb. am 17/08/1975 in Dessie, Äthiopien genehmigt durch die Fakultät für Verfahrens- und Systemtechnik der Otto-von-Guericke-Universität Magdeburg Gutachter: Prof. Dr.-Ing. Andreas Seidel-Morgenstern Prof. Dr. rer. nat. Franziska Scheffler Promotionskolloquium am 04. June 2010 Abstract In this thesis the potential of modulating solvent composition during chromatographic separation is investigated theoretically and experimentally. Hereby main focus is set on evaluating the potential of nonlinear gradient profiles in preparative liquid elution chromatography. As a case study was analysed the isolation of the second eluting component from a ternary mixture. Based on an experimental investigation, the changing thermodynamic equilibria and the effect of the gradient profiles on the shape of the elution profiles were studied theoretically.