Flame Ionization detection
Flame ionization detectors (FID) are the most commonly used gas chromatography detectors. They are high resolving and sensitive instruments that are widely used for analyzing most of the volatile organic compounds.
An FID is constructed with a small volume chamber into which the gas chromatograph’s capillary column is directly plumbed and where the flame is lit. The signal depends on the creation of charged particles produced from compounds by temperature in the flame.
In the absence of organic molecules in the carrier gas, the flame is relatively poor in charged particles.
The presence of an analyte gives a response assumed to be proportional to the concentration. The instrument’s response to the analyte in the unknown should be compared with the response to a standard.