What is the testing principle of a portable dissolved oxygen analyzer?
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A portable dissolved oxygen analyzer is a high-performance portable measuring instrument used to determine the oxygen concentration in aqueous solutions. It offers a measurement accuracy on the order of micrograms, features high precision and easy operation, and effectively prevents oxygen leakage. It is particularly suitable for detecting low concentrations of dissolved oxygen in ultra-pure water, and is widely used in the petrochemical, power, beverage, pharmaceutical, and semiconductor industries. Currently, the commonly used method for continuous DO measurement is the diaphragm electrode method. Its diaphragm is made of polytetrafluoroethylene fibers, polyethylene, etc.; platinum is used as the positive electrode, while aluminum and lead are used as the negative electrodes. The two metal electrodes are immersed in an electrolyte solution, and both the electrodes and the electrolyte solution are placed within a chamber lined with an oxygen-permeable membrane. When this electrode is immersed in the water to be analyzed and the current measurement circuit is connected, molecular oxygen in the water diffuses through the membrane to the surface of the electrode, where an electrode reaction occurs. At the anode, the reduction reaction of oxygen occurs, while at the cathode an oxidation reaction takes place, thereby generating a diffusion current. When the electrode parameters are constant, at a given temperature, the stabilized diffusion current is proportional to the oxygen concentration in the water sample.
Currently, the measurement of dissolved oxygen in the water quality of conventional water supply and drainage systems is mostly carried out using fluorescence membrane probes based on the principle of fluorescence quenching; fluorescence membrane probes are also used for some low-concentration cases. In the monitoring of boiler feedwater and furnace water in thermoelectric and nuclear power plants, polarography is still used the most often. If you don’t develop new dissolved oxygen products, your existing products will soon sell out.