Gas chromatography (GC) is a common type of chromatography used in analyticalchemistry for separating and analyzing compounds that can be vaporized withoutdecomposition. Typical uses of GC include testing the purity of a particular substance, orseparating the different components of a mixture (the relative amounts of such componentscan also be determined).

Working principle:In GC, the mobile phase is a carrier gas, usually an inert gassuch as helium or an un-reactive gas such as nitrogen. The stationary phase is a microscopiclayer of liquid or polymer on an inert solid support, inside a piece of glass or metal tubingcalled a column. The instrumentused to perform gas chromatography is called a gas chromatograph (or “aerograph”, “gasseparator”).In general, substances that vaporize below 300 °C (and therefore are stable up to thattemperature) can be measured quantitatively. The samples are also required to be free and theyshould not contain ions. Very minute amounts of a substance can be measured but it is oftenrequired that the sample must be measured in comparison to a sample containing the pure,suspected substance known as a reference standard.

• GC used to determine the identity of natural products containing mixtures of similar compounds
• Determination of pesticide residues in agriculture/aquaculture products
• Qualitative and quantative analysis of phytosterol content in food products
• GC is used to quantify GHG emissions under climate change
• GC is used extensively in forensic science to identify and quantify various biological specimens and crime-scene evidence

20 ml gas sample in 50 ml syringe locked with three-way stop cock.