The fluorescence method dissolved oxygen analyzer is a high-precision water quality monitoring device based on the principle of fluorescence quenching. By measuring the changes in the light signal after the interaction between fluorescent substances and oxygen molecules, it achieves rapid and accurate detection of dissolved oxygen concentration. By exciting fluorescent substances in the sensor with specific wavelengths of light (such as blue or green light), oxygen molecules shorten the duration or decrease the intensity of fluorescence, and their concentration is inversely proportional to the fluorescence phase difference. The instrument calculates the dissolved oxygen concentration by measuring the phase difference between the excitation light and the reference light, combined with temperature compensation.
It mainly consists of a fluorescent probe and a controller. The fluorescent probe includes blue LED, red light detector, fluorescent cap, temperature sensor, etc; The controller is responsible for signal processing, data display, parameter setting, data storage and transmission, etc.
Working principle: The built-in blue LED of the probe emits blue light of a specific wavelength, which is irradiated onto a special fluorescent substance coated on the surface of the fluorescent cap. The fluorescent substance absorbs energy and is in an excited state. Excited fluorescent substances will release red light and return to their ground state, while oxygen molecules in the water will interact with the fluorescent substance to suppress the release of red light, known as "fluorescence quenching". The higher the oxygen concentration, the stronger the quenching effect, the weaker the red light release intensity, and the shorter the lifespan. The photodetector in the probe captures the red light signal, and the controller analyzes the intensity or lifetime changes of the red light, combined with a preset calibration curve, to convert the current dissolved oxygen concentration or dissolved oxygen saturation of the water body.
Features:
Maintenance free: No electrolyte consumption, no need to replace electrode membranes, only regular cleaning or replacement of fluorescent caps, maintenance cycle can be extended to 6-12 months.
Quick response: No polarization time is required when starting up, and the measured response time T90 ≤ 60 seconds can be quickly put into monitoring.
Strong anti-interference ability: not affected by substances such as hydrogen sulfide, heavy metal ions, oils, pigments, etc. in water, with good measurement stability.
Easy to operate: Supports air calibration, no need for standard solution, intuitive controller interface, some models support touch screen operation and remote control.