Embodiments of the present invention provide columns for use in gas chromatography and methods of making and using such columns. The present invention provides a folded passage column: a fluid passage formed by joining a first channel in a first surface through a slot to a second channel in a second surface. In some embodiments, a folded passage column repeats that building block, joining a plurality of channels in a first surface with a plurality of channels in a second surface such that the channels link to form a continuous passage.