Gas chromatography differs from other Types of chromatography in the mobile phase is a gas and the components are divided as vapours. It is therefore utilised to separate and detect small molecular weight compounds from the gas phase. The sample is either a gas or a liquid that is vaporized in the injection port. The mobile phase for gas chromatography is a carrier gas, typically helium because of the low molecular weight and being chemically inert. The pressure is applied and the mobile phase moves the analyte through the pillar. The separation is accomplished using a column coated with a stationary phase. The equilibrium for gas chromatography is Partitioning, and the areas of the sample will partition i.e., disperse between the two phases: the stationary phase and the mobile phase.

Compounds with a gas chromatography affinity for the Stationary period spend more time in the column and for that reason elute later and have a more retention period Rt than samples that have a greater affinity for the cellular stage. Affinity for the stationary phase is driven largely by intermolecular interactions as well as the polarity of the stationary phase can be chosen to optimize interactions and for that reason the separation. Ideal peaks are Gaussian distributions and Symmetrical, because of the random nature of the analyte interactions with the column. The separation is hence accomplished by partitioning the sample between the gas and a thin coating of a non-volatile liquid stored onto a solid support. A sample containing the solutes is injected into a heated block where it is immediately vaporized and swept as a plug of vapor in the carrier gas flow to the column. The solutes are adsorbed in the stationary phase and then desorbed by a completely new carrier gas.

The process is repeated in every plate as the sample is moved toward the socket. Each solute will travel in its own rate through the column. Their rings will separate into different zones based upon the partition coefficients, and ring dispersing. The solutes are eluted one after another in the increasing order of this child, and enter into a sensor linked to the exit end of the column. Here they register a group of signals due to concentration changes and rates of elution on the recorder to get a plot of time versus the composition of carrier gas flow. The appearance time, height, width, and Area of those peaks can be measured to yield qualitative data.