Dissolved oxygen (DO) measurement is one of the most critical parameters in water quality analysis, widely used in environmental monitoring, aquaculture, and industrial process control. The three mainstream methods are polarographic, fluorescence, and electrochemical.
Polarographic Method
The polarographic method measures DO concentration by detecting the current generated when oxygen is reduced at the electrode surface. Advantages: fast response, high precision. Disadvantages: requires periodic electrolyte and membrane replacement.
Fluorescence Method
Based on oxygen quenching of fluorescent substances, this method calculates oxygen concentration by measuring changes in fluorescence lifetime. Advantages: maintenance-free, no flow requirement, excellent long-term stability. Disadvantages: higher initial cost.
Selection Guide
Polarographic: recommended for high-precision laboratory measurements. Fluorescence: ideal for long-term online monitoring. Electrochemical: suitable for portable field testing.