Hydrogen flame ionization detector is referred to as hydrogen flame detector, also known as flame ionization detector (FID: Flame loniza-tion Detector). It is a machine for testing hydrogen flame ionization, referred to as hydrogen flame detector, with high sensitivity, small dead volume, fast response, wide linear range, can be effectively combined with capillary column, and has become the most widely used detector for organic trace analysis.

Working principle:

The hydrogen flame detector is based on the combustion of hydrogen and oxygen in the air to produce flame as energy. When organic matter enters the flame, it is excited to produce ions under the high energy of the flame. There are a pair of electrodes at the upper and lower parts of the flame (the upper part is the collector and the lower part is the polarization). A certain voltage (150~300V) is applied between the two electrodes. The ions generated by the excitation of organic matter in the hydrogen flame move directionally under the action of the DC electric field between the electrodes, forming a weak current, and then flowing through a high resistance (107~1010) to take out the voltage signal, after amplification, it is sent to the secondary signal recording instrument to be recorded.

The detector adopts a cylindrical collector pole, quartz plus a metal nozzle, the polarization pole is a copper fork, the polarization pole collides with the nozzle mouth, and the ion chamber is a fully sealed structure. The polarization voltage of the gas chromatograph FID is 23OV, and the dual detector is located in an aluminum heating block, which is controlled by an internal heating heater and a platinum resistor. The hydrogen flame ignition of the gas chromatograph uses an electronic ignition gun to fire at the outlet end point. Due to the fully sealed structure, the outlet ignition is very easy.

System advantages:

1, high sensitivity (10-13~10-10g/S), about 1000 times higher than the sensitivity of TCD;

2, the detection limit is low, can reach 10-12g · g-1 g;

3, wide linear range, up to (106~107);

4. FID has a simple structure, the dead volume is generally less than 1uL, and the response time is only 1ms. It can be used with packed columns or directly with capillary columns, and is not sensitive to gas flow rate, pressure and temperature changes;

5. FID responds to all volatile organic compounds that can be ionized in the flame, and the relative response values for all hydrocarbon compounds (carbon number ≥ 3) are almost equal, and the relative response values for homologs (carbon number 23) in hydrocarbon organic compounds containing heteroatoms are almost equal, which can be directly quantitatively analyzed;

6, simple structure, excellent performance, stable and reliable, easy to operate;

Application areas:

1. VOCS online monitoring of pollution sources;

2. On-line monitoring of malodorous organic sulfides;

3. On-line monitoring of multi-point unorganized emission at the factory boundary;

4. Quantitative and qualitative analysis of total hydrocarbons (THC) and non-methane total hydrocarbons (NMHX) in the discharge pipeline;

5. Quantitative and qualitative analysis of alkene and cyclic aromatic hydrocarbons in the discharge pipeline;

6. Quantitative and qualitative analysis of dimethyl methyl phthalamide, alkanes and benzene in the discharge pipeline.