| According to "2013 China State of the Environment" in the content show that China’s rapid industrial development, human society continues to progress, accompanied by a rapid decline in produced water environment, the pollution problem has been highlighted. Ammonia one of the most common pollutants in water, as water pollutant emission control targets and basic project water environment monitoring and concern. As an important indicator of water to determine the degree of pollution, it helps to evaluate the "self-purification" state of water pollution and water, and for assessing the degree of eutrophication of water bodies, strengthen environmental protection are of great significance.This paper compares the main focus on "Determination of Water Ammonia (Nessler spectrophotometry)" analysis to explore the experimental system. Although this method has been identified as a national standard A method for monitoring and analysis but in everyday use, there is still a lot of problems can be improved and perfected. "-Nessler reagent spectrophotometric determination of ammonia in water quality" system to optimize the analysis of the experimental results of this paper, the experiment explored the impact of interference factor test, the standard method of adjusting reagent, experimental conditions and other issues.In this study, a complete selection of four kinds of representative water samples and two kinds of reference, quality control water samples as experimental subjects, through a systematic and comprehensive experiments, Nessler reagent spectrophotometric determination of ammonia in water analysis system to conduct a comprehensive optimization. This system results from the sample to include the following:(1) Save water samples:Water samples in sub-zero temperatures-cut off oxygen-under dark conditions, to extend the effective time saving, you can replace the existing methods of chemical acidification fixation.(2) Pre-treatment:flocculation method using membrane filtration (combined centrifuge) instead of medium-speed filter can effectively improve the problem of high blank experiment; the use of silicone oil distillation method can not effectively solve the problem of foam caused by the distillation of digestion; high concentration of the sample can be measured directly without dilution pretreatment.(3) Reagents:using Nessler dropping potassium sodium tartrate solution supernatant after use, can effectively reduce the blank experiment; for potassium sodium tartrate turbid water quality samples can be removed using the reagents; Given Nessler’Sreagent highly toxic, this experimental basis to ensure the method detection limits and accuracy of the results, based on the Nessler single sample single decreasing amount of 1.3mL, for cleaner water samples (lower ammonia concentration) Nessler’Sreagent single sample single decreasing amount of 1.2mL.(4) a clear and stable conditions for color body:the color value of 13.0 to 13.6 pH system, room temperature 25 ℃,the expansion colorimetric time to 10～30min.Through this study, to reduce or eliminate the interference factor system to ensure the accuracy of the experimental results, combined with laboratory analysis, the effective analysis of low intensity and improve the efficiency of the analysis. Reducing the use and emissions of reagents (especially poisonous agents), reducing the environmental and health hazards. |
