Chromatographic methods are important for the isolation and purification of value added products. This is partly due to the increasing availability of highly selective stationary phases. At the other end there are various techniques available how to apply efficiently chromatographic columns. This second aspect will be the focus of the lecture.

An overview will be given regarding several possible operating modes applicable to perform separations with a preparative focus. Antipodes considered are a) isocratic and gradient elution, b) single column and multicolumn arrangements and c) discontinuous and continuous processes.

There are several models available to compare the different concepts. A short overview will be given. In particular equilibrium theory will be considered which provides a powerful tool to understand migration processes in chromatographic processes and thus to evaluate the process performance.