Follow
Gas chromatography (GC) is an analytical technique used to separate and identify the presence or absence and/or quantity of chemical components in a sample mixture. These chemical elements are usually organic molecules or gases. For GC to be successful in their analysis, these elements must be volatile, typically with molecular weights below 1250 Da, and thermally stable so that they do not degrade in the GC system. GC is a widely used technique across many industries, including:
=>> Quality control in the manufacture of many products, from automobiles to chemicals and petrochemicals, to pharmaceuticals
=>> Research objectives range from meteorite analysis to natural products
=>> Safety and monitoring from environmental sampling, microplastics and food and wine to forensics.
Gas chromatographs are often hyphenated to mass spectrometers (GC-MS) to enable chemical element identification.
How does it work?
As the name suggests, GC separation uses a carrier gas, which plays the part of the mobile phase. The carrier gas transports the sample molecules through the GC system, ideally without reacting with the sample or damaging the instrument components.
=>> The sample is first introduced into the gas chromatograph (GC), either with a syringe or transferred from an autosampler that can also extract chemical components from solid or liquid sample matrices. The sample is injected into the GC inlet through a septum that enables injection of the sample mixture without losing the mobile phase.
=>> Attached to the inlet is the analytical column, a long (10 – 150 m), narrow (0.1 – 0.53 mm internal diameter) fused silica or metallic tube containing a stationary phase coating on the inner wall.
=>> The analytical column is placed in a column oven that is heated to eliminate less volatile components during analysis.
=>> The outlet of the column is inserted into the detector which responds to the chemical elements emitted from the column to produce a signal.
=>> The signal is recorded by acquisition software on a computer to generate a chromatogram
