What are the main methods for measuring dissolved oxygen in water?
The main methods for measuring dissolved oxygen in water are: iodometric method, electrochemical probe method, conductivity method and fluorescence method. Iodometry is the earliest method used to measure dissolved oxygen in water and is also the benchmark method for measuring dissolved oxygen in water. When the water contains some reducing substances such as sodium nitrite, sulfide, thiourea, humic acid or tannin, it will cause greater interference to the iodometric titration data. In this case, the electrochemical probe method is recommended. . Electrochemical probe method instruments are widely used in practical work due to their fast measurement speed, stable results, accurate data, and low interference. Its working principle is that when oxygen molecules in the water pass through the diaphragm, they are reduced by the working electrode. This process produces a The oxygen concentration is directly related to the diffusion current, and the dissolved oxygen concentration in the water is calculated by measuring this diffusion current. The current method standard for electrochemical probe method to measure dissolved oxygen is HJ 509-2009. This article mainly discusses and analyzes the operation and maintenance details of the electrochemical probe method for measuring dissolved oxygen in water, so as to fully understand the performance characteristics of the instrument and thereby improve the measurement accuracy of the dissolved oxygen meter.
The electrochemical probe method for measuring dissolved oxygen greatly facilitates the determination of dissolved oxygen in water and improves work efficiency. Its portable design, low maintenance, high accuracy and good repeatability make the electrochemical probe method of dissolved oxygen meter not only in the laboratory It is widely used inside and more widely in on-site portable measurement and automatic online water quality monitoring stations. However, in order to make every measurement value accurate, it is inseparable from the correct use of the instrument electrodes by the instrument user. Regular maintenance. Diligent maintenance of the instrument is an effective measure to improve the measurement accuracy and extend the service life of the instrument.
