The fluorescence method of dissolved oxygen used in the fluorescence method of trace dissolved oxygen analyzer is a method for measuring dissolved oxygen based on the principle of fluorescence quenching, and it has a wider range of applications than the coated electrode method and the iodometric method.
Fluorescence Dissolved Oxygen Analyzer is based on the principle of quenching active fluorescence by specific substances in physics. The fluorescent material at the front of the sensor is a special platinum metal porphyrin compounded with a polyester foil that allows gas to pass through. The surface is coated with a black light barrier material to avoid interference from sunlight and other fluorescent materials in the water. The modulated green light shines on the fluorescent material to excite it and emit red light. Since oxygen molecules can take away energy (quenching effect), the time and intensity of red light excitation are inversely proportional to the concentration of oxygen molecules. The synchronized red light source is used as a reference to measure the phase difference between the red light and the reference light, and compare it with the internal calibration value to calculate the concentration of oxygen molecules, and output the final value after temperature compensation. In the past 50 years, the current method and polarography method have been used to measure dissolved oxygen.
This method has played a very important role in the monitoring of dissolved oxygen in municipal and industrial wastewater. However, the traditional electrochemical method uses membranes, electrodes and electrolytes, which will cause many problems. Even if it is regularly maintained, it still cannot Get accurate measurement results.
The new fluorescent technology has no membrane and electrolyte, almost no maintenance, excellent performance and easy to use. There is no need to replace the fluorescent cap, the use cost is lower, and it is not interfered by chemical substances such as sulfide.