The Research Of Droplet Analysis And Water Quality Quantitative Detection

Droplet analysis technique includes two major function: firstly, it can be usedfor the qualitative identification of the liquid; secondly, it is a quantitative methodfor measuring the liquid parameters.At present, research of the technology at home and abroad mainly concentrateson the first function, i.e. more researches on droplet analysis methods and dropletanalyzers to acquire liquid droplets fingerprints which contain more liquidinformation more convenient. The above researches laid a good foundation for thequalitative identification of the liquid drop analysis technology, but they were shortof acquiring the specific water quality parameters of the analyzed liquidquantitatively. In this paper, droplet analysis technique is used to acquire liquidinformation qualitatively, at the same time, more researches focus on how to detectthe water quality indicator parameters quantitatively, which makes a good basis forexpanding the practical application of the droplet analyzer.Water quality and ecological environment are closely related. It is important todetect the water quality and protect the water resources. There are many indicatorscan describe water quality, among them, dissolved oxygen, salinity, pH, temperatureand trace of heavy metals content are the most important. Especially in the aquatichealthy breeding, the precise control of the above parameters is the key factor. Aboveall, we focus on the quantitative detection of the following water quality indicators-dissolved oxygen, salinity and pH, which based on the quantitative detection ofdroplet analysis technique.The main work of this paper is summarized as followings:1. Combining the fiber optic dissolved oxygen method and fiber optic capacitivedrop technology. The quantitative detection of dissolved oxygen can be realizedwhile acquiring the liquid droplets fingerprints. Based on fiber optic, capacitive droptechnology, introducing the fiber optic dissolved oxygen probe to solve the technicalproblem of fusing the two methods. Then the experimental device is set up, whichincludes: the choice of the fluorescent light source, fiber optic dissolved oxygenprobe and the photoelectric conversion element, the designing of emitter structure,the processing circuit of dissolved oxygen and re-building the experimental device offiber optic, capacitive drop setup.2. Establishing the best dissolved oxygen detection model. Doing experiments based on30different dissolved oxygen concentration of the liquid, studying differentdissolved oxygen detection models based on the experiments results, through thecomparative analysis of models, the best dissolved oxygen detection model can beobtained.3. Analyzing the relationship of fiber-optic signal in drop technology and salinity.Studying the salinity detection model. Utilizing the experiments device, conductexperiments on20different salinity solutions. Through the analysis of experimentalresults, we establish the salinity detection model based on the fiber signal and areaunder the fingerprint curves in the liquid droplets fingerprints. By comparing severalexperimental results based on several models, we obtain that three-level BP neuralnetwork model detects optimally by using fiber average signal of the input vector.4. Discussing the relativity between droplet analysis methods and the pH. Doingsome experiments with several lower alkaline solution, we find that fiber, capacitivedrop analysis is not appropriate for the detection of pH. We have also do someresearch on the strong alkaline solution of several high pH, after analyzing theexperimental results, concluding that fiber capacitive drop analysis method is notsuitable for the strong alkaline solution.5. Analyzing the possible impact of the temperature on the fingerprint anddetection of liquid, dissolved oxygen and salinity. A method of temperaturecompensation is given.