Gas chromatography is a laboratory technique used to separate and analyze compounds in a mixture. It works by vaporizing the sample and passing it through a column filled with a stationary phase. Different components of the mixture travel at different speeds, allowing them to be separated as they exit the column. The separated compounds are then detected, often using a mass spectrometer or a flame ionization detector. This method is widely used in various fields, including environmental testing, forensic science, and food safety, to identify and quantify substances in complex mixtures.