Common Detection Technologies of Toxic and Harmful Gas Detectors
When using gas detectors to test toxic gases, multiple gas‑detection technologies are available. Nevertheless, no single technology can realize fast, low‑cost and highly‑accurate measurement for specific toxic gases. Hence, various factors shall be considered when selecting a proper toxic‑gas detection method.
① Colorimetric Tube Measurement Technology Apart from toxic‑gas alarms, colorimetric tube technology is still applied for toxic‑hazardous gas detection in industry and environmental protection. Based on chemical color‑developing reactions, its biggest advantage is making up for the lack of suitable sensors for instrumental measurement.
② Electrochemical Sensor The electrochemical sensor is a common and mature detection technology for toxic‑hazardous gas measurement in portable gas detectors. It features compact size, low power consumption, favorable linearity and repeatability, and relatively long service life.
③ Semiconductor Sensor A semiconductor sensor consists of detecting elements made of metal‑oxide semiconductor materials. When interacting with gases, surface adsorption or chemical reactions take place, which trigger changes in conductivity, volt‑ampere characteristics or surface potential characterized by carrier movement. It can measure combustible gases at percentage‑level concentrations as well as toxic gases at ppm‑level concentrations.
④ Ionization Detector Commercially available ionization detectors mainly include the Photoionization Detector (PID) and Flame Ionization Detector (FID). They are widely adopted toxic‑gas detectors for gas‑chromatography equipment. When manufactured as standalone instruments, these two sensors become mainstream means for detecting volatile organic compounds (VOCs).
