Design Of A Chlorophyll Detector Using Fluorescence Method

Chl a (Chlorophyll a) concentration is highly correlated to the phytoplankton density and is used to estimate the primary productivity and biomass in the ocean. The detection of Chl a is quite important in the protection of marine ecological environment. Research of Chl a is significant in the study of the carbon cycle process in the ocean, and the Chl a concentration is also a useful parameter in monitoring water bloom and red tide. Therefore, It is necessary to design and develop a high-sensitivity, low-power, real-time and continuous detecting instrument for deep sea in situ measurements of Chl a.Based on discussions about domestic and international development of the Chl a detecting instruments, a new Chl a detector which used fluorescence measuring techniques was designed. The detector integrated the mechanics, optics, electronics, computer technology, and achieved high-sensitivity, high-stability, low-power performance.Experiments were designed to test the capacities of the detector. And the results showed that:the system noise was less than 0.1mV, the detecting accuracy was up to 0.04μg/L, the linear range was 0.05～100μg/L, and the average current consumption was only 35.7mA, all of which indicated the detector was able to make a good performance in the deep sea Chl a measurements.The paper included 7 chapters:Chapter 1 introduced the background and significance of the research, the domestic and international development of Chl a detecting instruments. And a high-sensitivity, low-power Chl a detector was proposed to design in the chapter.Chapter 2 introduced the fluorescence analysis and Chl a fluorescence spectrum. The theory of quantitative measurement of Chl a was described. And the relative relationship between Chl a concentration and the fluorescence intensity was derived.Chapter 3 described the structure design of the instrument as a whole and every single part.Chapter 4 described the system hardware design.Chapter 5 described the system software design.Chapter 6 introduced the experiments and result analysis.Chapter 7 was a summary of the paper and a prospect for the further research.