Gas chromatography is a separation technique in which a sample mixture is introduced into a stream of gas (the mobile phase, typically H2 or He) which flows over the surface of a film (the stationary phase) that coats either spherical particles (packed column) or the wall of a long, narrow tube (capillary column). Separation is based on differences in volatility and the relative affinity of the different sample components for the stationary phase.
This image shows a typical bench-top gas chromatograph-mass spectrometer. Click on the any part of the image to jump to that page, or use the trail guide below to follow in sequence:
GC-MS: Injectors/Detector → Columns → Mass Spec