Gas-liquid chromatography has a stationary phase composed of

• A. A solid support
• B. A liquid layer adsorbed on the column packing
• C. A gas
• D. A vapor

Answer: (B)

In gas–liquid chromatography, separation relies on partitioning the analytes between a mobile gas and a liquid stationary phase. The stationary phase is a liquid layer adsorbed on the column packing, forming a thin film that coats the inert solid support inside the column. As the carrier gas flows, each compound distributes between this liquid film and the gas phase, so compounds with greater affinity for the liquid stay longer in the column and elute later than those with less affinity.

This is different from a solid support alone, which would be the physical scaffold but not the phase that interacts with the analytes in gas–liquid chromatography. The carrier gas is the mobile phase, not the stationary one, and a vapor is not the fixed liquid film that creates the separation.