Volatile Organic Gas AnalyzerIt is an instrument used to detect the concentration and composition of volatile organic compounds (VOCs) in the environment.

　　Volatile Organic Gas AnalyzerWorking Principle:

Photoionization detection (PID): Using a specific wavelength ultraviolet light source (such as a 10.6eV vacuum ultraviolet lamp) to bombard gas molecules in an ionization chamber, ionizing volatile organic gas molecules to form positively charged ions and negatively charged electrons. These charged particles form weak ion currents under the action of the electric field on the polarizing plate. After amplification by a high-sensitivity microcurrent amplifier, they are captured by a data acquisition system and sent to a computer for analysis and processing, ultimately converted into readable VOCs concentration data. Its advantages include the ability to detect extremely low concentrations of VOCs using sensors with smaller volumes, low power consumption, and minimal temperature sensitivity.

Electrochemical sensor: Gas molecules enter the sensor through tiny capillary type openings, pass through a hydrophobic barrier layer, and reach the electrode surface. They undergo oxidation or reduction reactions with the electrode material, forming a current proportional to the gas concentration. The concentration of VOCs can be determined by measuring the current.

Hydrogen flame ionization detection (FID): Using the flame generated by the combustion of hydrogen and air as energy, volatile organic compounds undergo chemical ionization at high temperatures when entering the flame, producing a large amount of ions. These ions form an ion flow under the directional action of a high-voltage electric field, and after high impedance amplification, become an electrical signal proportional to the amount of organic matter. FID detectors respond to almost all volatile organic compounds, with advantages such as high sensitivity, small base flow, wide linear range, small dead volume, and fast response. However, they require three gas sources and their flow rate control systems, and have strict requirements for explosion prevention. They cannot detect substances such as water, carbon monoxide, carbon dioxide, nitrogen oxides, hydrogen sulfide, etc., and are relatively expensive.