Common Detection Methods for Toxic‑hazardous Gas Detectors
Various gas‑detection technologies are available for toxic‑gas measurement. Meanwhile, no single technology can achieve fast, low‑cost and highly‑accurate measurement for specific toxic gases. Therefore, multiple factors shall be taken into account when selecting an appropriate toxic‑gas detection method.
① Colorimetric Tube Measurement Technology Besides toxic‑gas alarms, colorimetric tube technology is still adopted for toxic‑hazardous gas detection in industrial environmental protection. Based on chemical color‑developing reactions, this measuring method can make up for the shortage of unavailable suitable sensors.
② Electrochemical Sensor As a common and mature detection technology, electrochemical sensors are widely used in portable gas detectors for toxic‑hazardous gas measurement. They feature small size, low power consumption, good linearity and reproducibility, as well as relatively long service life.
③ Semiconductor Sensor The sensing element of a semiconductor sensor is made of metal‑oxide or metal‑semiconductor‑oxide materials. Interaction with target gas triggers surface adsorption or chemical reactions, which lead to changes in conductivity, volt‑ampere characteristics or surface potential related to carrier movement. It can measure combustible gases at percentage‑level concentration as well as toxic gases at ppm level.
④ Ionization Detector Commercially available ionization detectors include Photoionization Detector (PID) and Flame Ionization Detector (FID). They are widely used toxic‑gas detectors for gas chromatographs. When manufactured as standalone instruments, they become common detection means for volatile organic compounds.
