Study On Quantitative Analysis Of Spectrum Of Kjeldahl Nitrogen In Yangtse And Jialing River Valley (the City Zone Of Chongqing)

The problem of water eutrophication was appeared about from 1960s. It would pollute the water resource of the world all the time and influence the production and people's life. Along with the increasing of the urban population and the more faster development of industry and agriculture in our country, the environmental pollution is becoming more seriously day by day, and the water quality is also becoming much more worse, the danger brought is prominent so that it would have a important means to solve water eutrophication is keep away the pollution as early as it occurred. Anyway, it is necessary for understanding and controlling the state of eutrophication through setting up standard analytical method and determination analysis to the main materials in eutrophication substance such as Nitrogen. Due to the primary eutrophic salt in the water is total phosphorus and total nitrogen in which most important substance is the concentration of Kjeldahl Nitrogen. It is important to realize the zoology of valley through the local monitoring the Kjeldahl Nitrogen content.This paper mainly discussed the method of the Kjeldahl Nitrogen determination in the water by UV—spectrophotometer. Researched the preparation of the standard curves and the confection of the experiment reagents. Impact factors of the color developing reagents, impact of the interfere on to Kjeldahl Nitrogen and the eliminating interferential matter in the lab also have been studied. The best conditions in the lab under method of Nessler reagent spectrophotometry were: the best color-developing time is 10 minutes, the color-developing temperature is about 25℃, the range of pH value is 11.8～12.4, the dosage of color-developing is 1.5ml. We have studied the effects of Nitric acid nitrogen, Nitrous acid nitrogen, organic substance, and metal cation to determination of Kjeldahl Nitrogen, and setted up the lab method to wipe off interferential matters. The Nitric acid nitrogen and Nitrous acid nitrogen could be separated through the nitration or distillation to concentration the inorganic element nitrogen. The organic substance in water sample could be eliminated by using boil sample method and at different pH value, or headed up during the process of nitration occurred, as samples would be low boilling point. The effection of metal cation could be eliminated by adding some concealed reagent such as Potassium sodium tartrate tetrahydrate.After completing the study of Kjeldahl Nitrogen determination for the samples in...