What is the difference between iodometric measurement and portable dissolved oxygen meter
Environmental monitoring technology is constantly changing and updating, and various types of rapid measuring instruments are also emerging. Similarly, dissolved oxygen measuring instruments are constantly being updated and converted to meet the convenience of users. Portable dissolved oxygen meters are popular with more and more users because they are easy to carry, suitable for on-site measurement, less interference, and fast. In recent years, in response to environmental protection, we have advocated starting from everything and everyone around us. Environmental monitoring technology is constantly changing and updating, and various types of rapid measuring instruments are also emerging. Similarly, dissolved oxygen measuring instruments are constantly being updated and converted to meet the convenience of users. Portable dissolved oxygen meters are popular with more and more users because they are easy to carry, suitable for on-site measurement, less interference, and fast. However, because the analysis and testing principle and method of the portable dissolved oxygen meter are different from the national standard iodometric method, it is necessary to conduct a comparative experiment with the national standard method to determine the accuracy and reliability of the analysis method. For most of the polluted surface water and industrial wastewater, the modified iodometric method or membrane electrode method must be used, while the portable dissolved oxygen meter and the membrane electrode method are based on the diffusion rate of molecular oxygen through the membrane to measure dissolved oxygen in water. For polluted water samples, the portable dissolved oxygen meter method is obviously more superior than the iodometric method. Therefore, this experiment selects clean surface water as a sample, and compares and analyzes the results of the determination of dissolved oxygen in water samples by the portable dissolved oxygen meter method (hereinafter referred to as the dissolved oxygen meter method) and the iodometric method (GB7489-87). This is a test of the confidence and precision of the dissolved oxygen meter method for the determination of dissolved oxygen in water samples. Instruments: portable dissolved oxygen meter, calibrated glassware. Reagents: All solutions and reagents are prepared according to national standard methods and are within the validity period. The dissolved oxygen in the same water sample is compared with the portable dissolved oxygen meter and the iodometric method. According to the results of the two methods, the DIXON test and the precision test are carried out, and the confidence level is set at 95%. The comparison results show that the two methods There was no significant difference between the determination results, and the precision met the quality control requirements of water quality monitoring. Put the same clean surface water sample in a constant temperature box at 20 °C to keep the temperature of the water sample at 20 °C, and measure its dissolved oxygen concentration with the dissolved oxygen meter method and the iodine method (GB7489-87) respectively, and measure continuously for 5 days. , measured 5 times a day. The measured data are recorded in Table 1 and Table 2. (Click on the picture to enlarge it to view) Proved by the above experiments, the confidence test and precision test of the two methods show that there is no significant difference between the two methods, and it can be considered that the two methods have consistency in the determination results of the same sample. That's all for the above content, I hope friends can understand the results of the two methods of measurement and the results of the table analysis.
