Gas-liquid chromatography (GLC), also known as gas chromatography (GC), is a highly versatile analytical technique used to separate, identify, and quantify volatile and semi-volatile compounds present in a mixture. It utilizes the principles of partitioning and selective adsorption to separate analytes based on their differences in volatility and affinity for the stationary phase.
In GLC, the sample, usually a gaseous or liquid mixture, is injected into a narrow column packed with a stationary phase (-- a liquid film coated onto an inert solid support or a capillary column with a stationary phase film). A carrier gas, typically an inert gas such as nitrogen or helium, is passed through the column, carrying the sample components along. As the components traverse the column, they partition between the stationary phase and the moving gas phase, resulting in differential retention times.
As the components elute from the column, they are detected by a detector located at the end of the column. Common detectors used in GC include flame ionization detectors (FID), thermal conductivity detectors (TCD), and electron capture detectors (ECD). These detectors generate signals proportional to the concentration of each component in the mixture.
Gas-liquid chromatography is widely used in various fields including forensic analysis, environmental monitoring, pharmaceutical analysis, and food science. It offers high sensitivity, excellent resolution, and fast analysis times. Moreover, with the availability of different stationary phases and detectors, GLC can be adapted to separate a wide range of chemical compounds of varied volatility and polarity.
