Cyclic organosiloxanes were chemically bonded to silica gels and evaluated for possible use in microcolumn gas chromatography of light hydrocarbons in extraterrestrial atmospheres. DRIFT and solid state NMR spectroscopic studies confirmed the bonding of the siloxanes onto the silica surface. The surface concentration of the phases, which varied with the reactivity of the siloxane bond toward proton attack, were in the range of 0.31 μmol m−2 for octaphenylcyclotetrasiloxane to 2.39 μmol m−2 for hexamethylcyclotrisiloxane packings. Of the five columns investigated, hexamethylcyclotrisiloxane and pentamethylcyclopentasiloxane bonded phases seem to provide good separation of the test solutes presumably due to their somewhat higher surface coverage. All the columns gave similar H vs. ū curves with a shallow and flat minimum at the optimum region. The phases are thermally stable up to 300°C and allowed fast analysis of C1−C4 hydrocarbons under isothermal conditions.