Gas chromatography (GC) is an analytical chemistry technique used in testing complex mixtures like food, drugs, and petroleum products. It allows researchers to identify, separate, analyze and purify the individual components in a mixture. Using GC, scientists can qualitatively analyze and quantitatively measure each solute in a mixture.

How Does Gas Chromatography Work?

At the core of Gas Chromatography is a long capillary column inside an oven. The column is coated with a thin film of stationary liquid or solid phase. The mixture is injected into the column and carried by an inert gas known as the mobile phase. As the mixture travels through the column, the different components interact differently with the stationary phase based on their chemical properties. Those that interact less with the stationary phase move faster through the column compared to others. This allows the separation of the individual analytes as they exit the column at different time intervals, forming peaks in a chromategram. A detector measures the eluted analytes and converts them into electrical signals plotted against time.

Components of a GC System

The key components include an inlet system to introduce the sample into the GC column, a temperature-controlled oven that houses the column, a carrier or mobile gas to push the analytes through the column, and a detector. Common inlet systems are split/splitless inlets and on-column inlets. Typical ovens allow temperature programming from ambient to 450°C. Helium, hydrogen and nitrogen are frequently used carrier gases due to their inert nature. Popular detectors are flame ionization detector (FID), thermal conductivity detector (TCD), and mass spectrometer (MS).

Get More Insights On- Gas Chromatography