What are the measurement methods for oxygen gas concentration detectors?
1, Instrumentation method: an efficient and convenient mainstream detection method
The instrument method, with its advantages of fast response speed, easy operation, and real-time reading, has become the mainstream choice in industrial, civilian, and other scenarios. There are three common methods: electrochemical method, paramagnetic method, and ultraviolet absorption method
Electrochemical method: The core is to use the chemical reaction between oxygen and the electrodes and electrolyte inside the sensor to generate electrical signals. The intensity of the electrical signal corresponds to the concentration of oxygen, and the instrument processes the signal to obtain the concentration value. This method has a compact structure and is suitable for making portable gas concentration detectors. It can quickly capture concentration changes and has a relatively low cost. It is widely used for real-time monitoring in workshop inspections, enclosed spaces such as underground mines and storage tanks. The on-demand measurement feature makes the operation more flexible.
Paramagnetic method: Based on the strong paramagnetism principle of oxygen, oxygen will be attracted by a magnetic field and will change the magnetic field distribution after entering the detection chamber. The instrument calculates the oxygen concentration by sensing this change. This method has strong stability, minimal interference from other gases, and high accuracy, making it suitable for scenarios that require high detection accuracy, such as monitoring of medical equipment ventilators, precision industrial production, etc. However, due to the relatively
large size of the equipment, it is more commonly used for fixed monitoring.
Ultraviolet absorption method: Utilizing the absorption characteristics of oxygen towards specific wavelengths of ultraviolet light, the concentration is calculated by measuring the degree of absorption of ultraviolet light. This method has fast response speed, wide linear range, and can maintain stable detection in higher concentration ranges. However, it requires high optical components of the equipment and is often used for precise monitoring in specific industrial scenarios.
2, Chemical analysis method: suitable for offline precise determination
Chemical analysis method quantitatively detects oxygen concentration through chemical reactions. Although it cannot be read in real time, it has high accuracy and low cost, and is suitable for laboratory calibration or offline sampling detection. Common methods include iodometric method and colorimetric method:
Iodometric method: using oxygen to oxidize potassium iodide to generate iodine, and then determining the amount of iodine through titration reaction to calculate the oxygen concentration. The principle of this method is mature, the operation steps are clear, and no complex equipment is required. It is suitable for calibrating gas concentration detectors or offline analysis of oxygen content in specific environments. However, the operation cycle is long and not suitable for real-time monitoring scenarios.
Colorimetric method: Using oxygen to react with specific chemical reagents to generate colored substances, the color depth of the colored substances is related to the concentration of oxygen, and the concentration is determined by comparing with standard color levels or measuring with instruments. This method is easy to operate, low in cost, and suitable for rapid qualitative or semi quantitative detection on site. However, its accuracy is greatly affected by the stability of the reagents and the operating techniques, and it is often used in temporary detection scenarios where accuracy requirements are not high.
