Gas chromatography
Many types of detectors are used in gas chromatographic separations, with the most common are flame ionization, thermal conductivity, and mass spectrometry detectors.  In a flame ionization detectors, the separated sample from the column is directed into a flame.  By creating a voltage near the burner tip and the detector, the ions that are produced from the flame travel towards the detector.  Flame detectors are not capable of detecting H2O, CO2, SO2, and CO.