Chlorine (Cl₂) is a strong oxidant and has corrosiveness. When using Cl₂ to test some sensors, corrosion-resistant materials should be used in the testing system. Polytetrafluoroethylene (PTFE) or electroplated and polished stainless steel are recommended.

Before testing products with Cl₂ standard gas, it is necessary to ventilate for a certain period of time to rinse the inner wall of the gas pipeline. Otherwise, the concentration of Cl₂ is low in the initial stage of ventilation, resulting in a very slow signal output of the sensor. Through our multiple tests, after using Cl₂ standard gas with a standard concentration of 10 ppm, a gas pipeline with a length of 20 cm, and rinsing the pipeline at a flow rate of 0.5 L/min for 8 to 9 minutes, then introducing the gas into each sensor for testing can obtain relatively accurate test results.