Cross-Interference in Gas Sensors – Shortcomings of Gas Detection Instruments
It must be emphasized that there is currently no gas sensor with specific effects for a certain gas, which means that no gas sensor is yet effective for detecting specific gases. For example, a gas sensor labeled as detecting carbon monoxide may react with hydrogen gas in the detection environment to obtain a signal higher than the actual carbon monoxide concentration, which is called sensor cross interference. The task of manufacturers is to minimize this cross interference through various physical or chemical methods, such as using filter membranes and different circuit parameters to minimize the reaction of non test gases.
On the other hand, cross interference can also provide some convenience for instrument manufacturing in certain situations. For example, a carbon monoxide detector can be used to detect hydrogen gas, provided that there is only hydrogen gas present in the environment and no carbon monoxide. At the same time, this sensor needs to be calibrated with hydrogen gas. The common carbon monoxide/hydrogen sulfide dual sensor is also manufactured by manufacturers using the mutual cross interference characteristics of carbon monoxide and hydrogen sulfide sensors, which can simultaneously detect carbon monoxide and hydrogen sulfide, achieving the goal of one sensor detecting two gases simultaneously.
Due to technological limitations, gas sensors must undergo continuous calibration in order to obtain more accurate measurement results. Generally, the instrument must undergo a pump test before each use. If the measurement results of the instrument are within the error range, it can be used normally. However, if the test results deviate from the normal error range, the instrument must be recalibrated before use.
