Studies On Porous Plastic Fiber Optical Probe For Ammonia

The destroy of ocean zoology , pollution of environment and nutrition of seawater have seriously blocked development of economy and standard of living and threatened our survival environment. The concentration of nutrition salt in seawater is a important parameter for monitoring ocean zoology, and the concentration of ammonia(NH3) is a important index of ocean nutrition salt. Presently, at home, we also use the traditional sampling and experimental analysis for measuring ammonia. The traditional experimental analysis can't fill the demand of increasingly necessitous defending and decreasing disaster task and scientific research. It is necessary to developing a fast,sensitive,low-cost analysis method for detecting ammonia. The dissertation set up a new analysis method for detecting ammonia based on porous plastic fiber optic probe and get preferable applied results for seawater samples. This dissertation consists of the following three chapters: Chapter 1 is a literature review. In this chapter, we chiefly introduce two content: 1. Summarizes the methods of measuring ammonia and their principle,development and application, particularly emphasizing on the research and development of optics and optics fiber sensor for ammonia. 2. Introduce the basis of this research and choice of method. It also detailly introduce the principle of porous plastic optical fiber probe and describe the process flow of probe and the influence on probes of parameters in the fabrication of probe. Chapter 2 is the research on porous plastic fiber optical probe for ammonia with the indicator of aminofluorescein. In this chapter, we selected aminoflrorescin as indicator, Mthyl methylacryte as the monomer, Diethylene glycol dimethacrylate as cross-linking reagent and mixture of toluene and tetrachloride as porogen. The probe was prepared by a cross-linking co-polymerization technique. All effect was tested and selected the optimum prepare parameters. It showed that, at the optimum condition, the linear respond range to ammonia was 5~60ug/mL, detect limit was 1ug/mL. The test result on seawater sampling was satisfied and acidity,salinity,metal ion,amine and amino acid were not interfere. Chapter 3 is the research on porous plastic fiber optical probe for ammonia with the indicator of 2,7-dichloro-3,6-acrylate ester fluorescein. In this chapter, we decorated the fluorescein by acrylate ester group, and the double bond in the acrylate ester group could co-polymerize with monomer and cross-linking reagent. The performance of probe that prepared at the optimum condition was tested, the result showed that, the probe was sensitive to ammonia, the linear respond range to ammonia was 1~20ug/mL, detect limit was 0.5ug/mL, the probe was high selective and long life-span, it could continuous be used more than 2 months.