Biochemical Techniques and Instrumentation

2.6.3.6.1. Flame Ionization Detector (FID)

The flame ionization detetor measures the concentration of organic vapours in low levels from ppb to ppm. The components that elute from the column are ignited by mixing with gases, hydrogen and air. The organic compounds in the components burn in the flame to produce ions and electrons. These ions can conduct electricity through the flame. A large electrical potential is created at the burner tip and a collector electrode located above the flame collects the ions. The current resulting due to the burning of organic compounds is measured. This detector is mass sensitive rather than concentration sensitive. It has a large linear response range and low noise. It is less sensitive for non-hydrocarbon groups and insensitive to water, CO₂, SO₂ and other non combustibles. It is robust and easy to use, but unfortunately, destructive.

 Picture here