To understand cross-reactivity, it is important to first understand what cross-sensitivity is. Cross-sensitivity refers to the phenomenon whereby a sensor can react to other gases or substances even when no target gas is present. This reaction can affect the sensor's measurement of the target gas, potentially causing inaccurate readings. In simple terms, cross-sensitivity refers to the ability of a sensor to be sensitive to other gases in addition to the target gas. A gas detector's sensor identifies, isolates, and measures specific gases and reacts to different gases to varying degrees, giving an accurate reading of each gas in all circumstances.
For example, in a gas environment with H2 and CO, H2 sensor will react to CO gas to varying degrees. At this time, if a certain alarm value is set for the H2 detector, the Hydrogen detector will produce a false alarm in an environment without H2 but with CO.
Suppression is when a sensor fails to register the target gas when it is exposed to both the target gas and the suppressing gas, or when the suppressing gas causes the sensor to stop registering the target gas for a period of time after exposure to the suppressing gas (which could be hours or even days)
All of these errors can have adverse effects. Obviously, it is very dangerous when the sensor is reading incorrectly when toxic gases are present. And even if cross-sensitivity causes an over-reading or false alarm, unnecessary evacuation, ventilation and other unplanned downtime will result in wasted time and resources. Some manufacturers publish data and graphs on cross-sensitivity that provide some explanation of how cross-sensitivity affects the readings of their products. However, it is important not to rely too much on this data: electrochemical sensors can vary greatly from one another, manufacturers may change their sensor designs and specifications at short notice, and scientific understanding is constantly evolving. Therefore, it is a better practice to stay in touch with the manufacturer's technical support team, who are aware of the latest information and are best qualified to make recommendations on a given sensor. It is also wise to ensure that all personnel involved in gas detectors' detection understand the nature of cross-sensitivity and interference and are alert to the effects they may have.
1.Cross-sensitivity may cause the following effects:
Measurement error: When the gas sensor detects both target gas and non-target gas at the same time, measurement error may occur due to the existence of cross-sensitivity, causing the detection result to deviate from the true value.
False alarm: In some cases, cross-sensitivity may cause the gas detector or gas sensor to falsely alarm, that is, an alarm signal is issued when there is no target gas present, or an alarm signal is issued when the target gas concentration is lower than the alarm threshold.
Safety issues: In situations where high accuracy is required (such as chemical production, environmental monitoring, etc.), cross-sensitivity may cause safety hazards because incorrect detection results may mislead operators to make wrong decisions.Methods to reduce cross-sensitivity
2.In order to reduce the impact of cross-sensitivity, the following methods can be adopted:
Select highly selective sensors: When purchasing gas detectors, sensors with high selectivity should be given priority. These sensors usually have higher sensitivity to target gases and lower cross-sensitivity.
Use a combination of multiple sensors: For situations where multiple gases need to be detected simultaneously, a combination of multiple sensors can be used. Each sensor is responsible for detecting one or several specific gases, thereby reducing the risk of cross-sensitivity.
Perform cross-sensitivity correction: During the use of the sensor, its cross-sensitivity characteristics can be determined by experimental methods and corrected accordingly. This can be done by applying a known concentration of non-target gas to the sensor to observe its effect on the sensor output and adjust the sensor's measurement parameters accordingly.
Optimize sensor design: From the perspective of sensor design, the cross-sensitivity of the sensor can be reduced by optimizing the material, structure and other parameters of the sensor. For example, sensitive materials with higher selectivity can be used, or a more reasonable gas channel structure can be designed to reduce the interference of non-target gases.
Regular maintenance and calibration: Regular maintenance and calibration of gas detectors are also important measures to reduce the impact of cross-sensitivity. By regularly checking and replacing sensors, cleaning the sensor surface and other operations, the sensor can be kept in good working condition and accuracy. At the same time, regular calibration of sensors can ensure the accuracy and reliability of their measurement results.