Which type of GC detector is most commonly used? Explain its working principle and what are its limitations?
2013-09-11 09:46:11 liting
The most commonly used detector is the flame ionize detector. The sample is combusted with the help of fuel gas and oxidant in the detector body. Combustible sample components burn and produce ions and electrons which can conduct electricity through the flame. A large potential difference is applied at the burner tip and the collector electrode located above the flame and the current between the electrodes is measured. The detector is mass sensitive and response is not affected by carrier gas flow rate changes. However, the detector is not responsive to inorganic gases such as CO, O2, NH3, N2, CS2, CO2, etc.