The optical dissolved oxygen electrode is based on the principle of fluorescence quenching, and achieves dissolved oxygen measurement by detecting the interaction between fluorescent substances and oxygen molecules. It has significant technical advantages, which are reflected in stability and maintenance convenience

Fluorescence quenching principle: Accurately capturing changes in oxygen concentration

The core of fluorescence quenching method is to utilize the "quenching effect" of oxygen molecules on fluorescent substances. When fluorescent substances (such as ruthenium bipyridine complexes) are excited by blue light of a specific wavelength, they transition from the ground state to the excited state, and then return to the ground state by releasing fluorescent photons. If there are oxygen molecules in water, they act as strong oxidants and collide with excited fluorescent substances, causing them to return to the ground state non radiatively through energy transfer, resulting in a decrease in fluorescence intensity or a shortened lifetime. This phenomenon is strictly quantitatively related to oxygen concentration: the higher the oxygen concentration, the more significant the fluorescence quenching effect, and the more obvious the fluorescence intensity attenuation or shortened lifetime. The optical dissolved oxygen electrode integrates a light source, fluorescent sensing film, photodetector, and signal processing module to convert changes in fluorescence intensity or lifetime into dissolved oxygen concentration (in mg/L or ppm), achieving high-precision measurement.

Technical advantage one: Strong stability and outstanding anti-interference ability

Traditional polarographic dissolved oxygen electrodes rely on electrolytes and oxygen permeable membranes, which are susceptible to temperature fluctuations, pressure shocks, and flow interruption effects, leading to measurement errors or false alarms. The design of the optical dissolved oxygen electrode without electrolyte avoids problems such as electrolyte consumption and membrane fouling. At the same time, the fluorescence quenching process is insensitive to interference from magnetic fields, ion concentrations, etc., and can operate stably in complex environments. For example, in lake monitoring, optical dissolved oxygen electrodes can continuously record the diurnal variation curve of dissolved oxygen, clearly identifying the "oxygen peak" caused by algal photosynthesis and the "oxygen valley" formed by nighttime respiration, with better data repeatability than traditional electrodes.

Technical Advantage 2: Convenient maintenance and lower long-term costs

Optical dissolved oxygen electrodes do not require polarization or electrolyte replacement, and only require regular cleaning of the optical window (such as once a year), reducing maintenance time from several hours for traditional electrodes to one minute. Its sensor is equipped with an intelligent chip that can store calibration history, plug and test, and has simple online installation and operation. In contrast, polarographic electrodes require monthly checks for the integrity of the oxygen permeable membrane, regular replacement of electrolyte and membrane, high maintenance costs, and cumbersome operation. In addition, the replacement cycle of the membrane components of the optical dissolved oxygen electrode is as long as one year, which is much longer than the 1-3 months of traditional electrodes, further reducing long-term usage costs.