A gas chromatograph separates volatile gaseous compounds carried by an inert gas such as helium, nitrogen, argon or hydrogen across a solid stationary phase. Components in a gas chromatograph include a sample injector, flow controller, GC column, column oven, a detector, and a computer for data acquisition and analysis. A combination of electronic sensors and pumps maintain either a constant or variable mobile phase flow rate from 0.001 to 100 mL per minute. GC instruments typically have a maximum temperature of 350C to 450C.
Gas Chromatographs can be equipped with several types of detectors including: a flame ionization detector (FID), a thermal conductivity detector (TCD), a flame photometric detector (FPD), an electron capture detector (ECD), and even a mass spectrometer, for example. Gas chromatography is a powerful standalone application used in many industries, especially environmental testing. However, GC instruments are also found in combination with mass spectrometers, refining the GC separation with additional mass analysis. Fast run times and robust data acquisition and analysis software are important features in a gas chromatograph.