Real-Time Monitoring of Dissolved Oxygen at a Vicinity of an Aquatic plant

Real-time monitoring of dissolved oxygen (DO) concentration at a vicinity of an aquatic plant in water by the fluorescent quenching method is discussed. Ru(II) complex (Tris(2,2'-bipyridyl) ruthenium(II) chloride) was used a fluorescent probe, whose fluorescence was quenched by DO. The fluorescence of the Ru(II) complex at a vicinity of the aquatic plant was excited by a semiconductor laser of 405 nm, and detected by a PMT. Experiment results showed that the DO concentration at the vicinity of Egeria Densa decreased with time in the respiration processes, while increased with time in the photosynthetic processes. It was further applied to monitor DO at vicinities of the aquatic plant in water environments containing heavy metal ions such as Cu2+.