A removable column-switching device for a commercially available gas chromatograph has been developed. To this end, the challenges of the equipment's high temperature stability, of the flow of gas through stand-by columns, of catalytically effective stainless steel surfaces, of the cooling trap effects within valves and the limited oven space are dealt with. The developed column-switching system was investigated in terms of dead volume (tailing factor), adsorption (Grob test) and degradation (Endrin test). This GC column-switching system shows comparable results with analyses that do not employ column switching. For example, it was possible to avoid effects, such as adsorption and decomposition. This system can automatically test the suitability of as many as eight separating columns to analyze unknown samples. The GC column-switching system thus serves to increase efficiency in the selection or screening of stationary phases with GC method developments.