Gas Chromatography
Gas chromatography (GC) is a powerful and widely used analytical tool found in virtually every analytical laboratory. It is used for the separation, identification and quantification of the individual components of a complex mixture. Gas chromatographic analysis is a valuable tool used to identify and quantify unknown compounds, follow reaction kinetics and provide information on the purity of a product.
Gas chromatography is based on the principle that each component of a mixture will travel through a long capillary column at different rates. The capillary column is basically a long and narrow tube made of a lightweight inert material with an inside diameter of 0.1-0.53 mm. A carrier gas is used to move the sample through the column. Different chemicals in the sample will separate, or elute, from the column at different times, depending on how quickly they can move through the column.
The eluted chemicals are then detected by a detector placed at the end of the column. Different detectors can be used in GC including flame ionization detectors (FIDs), thermal conductivity detectors (TCDs), electron capture detectors (ECDs), flame photometric detectors (FPDs), and mass spectrometers (MSs). The detectors measure the properties of the eluted chemicals as they pass through and output an electrical signal that is correlated to the concentration of the chemical in the sample.
The signal produced by the detectors is then recorded and analyzed. Chromatographic software programs are used to generate a chromatogram, a graphical plot of signal intensity versus time (or in some cases, concentration versus time). The overall shape of the chromatogram can be used to confirm qualitative identification of the compounds present in the mixture as well as calculate the concentration of the individual compounds in the sample.
Gas chromatography can be used to analyze a wide range of compounds including volatile, semi-volatile and polar compounds. Its versatility and precision make it an invaluable analytical tool for a variety of industries including petrochemicals, pharmaceuticals, food and beverage, forensic, environmental and many more.
Overall, gas chromatography is a powerful analytical technique used for the identification, quantification and separation of compounds in a mixture. It has wide applications across different industries and has become an essential tool for analytical laboratories worldwide.
