The separation of a certain target component from a multicomponent mixture using isocratic preparative elution chromatography was studied theoretically. In particular, the important and most complicated case was considered that the target component does not elute in the first or last position. To specify the productivity of collecting this component different options are suggested to identify suitable times for fractionation. Using a conventional Craig model, capable to quantify chromatographic processes, the impact of several essential parameters (e.g. threshold concentration, desired purity, injection volume, separation factor between neighboring components, composition of the mixture) is evaluated for a ternary system based on parametric calculations. The paper provides simple tools to evaluate and optimize the productivity and other objective functions relevant in multicomponent preparative chromatography.