Question

What is a major requirement for an analyte in order for it to be separated by GC (gas chromatography)?

A. the compund must have a high atomic number

B. the compound must have absord UV-vis ligth

C. the compound must be sufficiently volatile

D. the compound must have a molar mass above 100

E. the compound needs to thermally unstable

Answer 1

The answer is C. The compound must be sufficiently volatile in order to carry out separation by Gas Chromatography (GC). GC is used to separate compounds in a mixture that can be vaporized without decomposing. As in other types of chromatographic techniques, GC also involves the action of a stationary phase and a mobile phase. In GC, the mobile phase is a gas, mostly an inert gas like Helium. The stationary phase is a microscopic polymer or liquid layer on a solid support.
Unlike column chromatography, GC is a gas-liquid chromatographic technique with a gaseous mobile phase and a liquid stationary phase and the setup often has a temperature control to enable easier vaporization of the components.

Hence, in order that a compound is separated by GC, the components have to be sufficiently volatile as the process involves the vaporization of the components and their retention on the stationary phase.