Chromatography (from Greek chroma "colour" and graphein "to write") is the collective term for a set of laboratory techniques for the separation of mixtures. Our definition refers to gas chromatography for environmental monitoring and analysing industries and applications, using equipment such as a GC monitor and / or GC analyser. GC technique Gas Chromatography (GC), also sometimes known as Gas-Liquid Chromatography (GLC), is a separation technique in which the mobile phase is a gas. Gas chromatography is always carried out in a column. These are typically "packed" or "capillary". GC is based on a partition equilibrium of analyte. This occurs between a solid stationary phase (often a liquid silicone-based material) and a mobile gas (most often Helium). The stationary phase is adhered to the inside of a small-diameter glass tube (a capillary column) or a solid matrix inside a larger metal tube (a packed column). Where is gas chromatography used? GC is widely used in analytical chemistry. The high temperatures used in gas chromatography make it unsuitable for high molecular weight biopolymers or proteins. This is because heat will denature them, frequently encountered in biochemistry. It is well suited for use in petrochemical, environmental monitoring and remediation, and industrial chemical fields. It is also used extensively in chemistry research.