Improvement On The Optimum Condition In The Experiment Of Determination Of Water Quality

The major works in the paper focus on the three substances in the water: volatile phenol, total phosphorus and ammonia nitrogen.In the paper, we determinate the concentration of volatile phenol of surface water by adopting 4-amido antipyrin spectrophotometry. Some conclusions have deduced from a series of experiments: there is no effect when you add distilled water about 15ml directly after filling 250ml sample when you distill the sample. What's more, it can avoid the interfering in the near of completing distilling. The method of chloroform extraction pure 4-amido antiprin is not only quick and simple but also can reduce the blank concentration and have stable property. The best time of color to develop is 10min. The order of adding reagent must not change according to the operating rules(GB7490-87) during the reaction of color to develop. In the experiment, adding oxidant- potassium persulfate instead of potassium ferricyanide could not only get the good effect but also decrease the pollution of environment. The best pH of color to develop is 10. Both of de-ionized water and phenol-free water can meet the requirements of environmental monitoring.This thesis studied the experiment conditions of determination of total phosphorus by photometry of tin chloride reduction We can draw some conclusions after series of tests as follow: The total phosphorus is about double dissolved phosphorus, which caa be used to make sure the multiple of diluting. The concentration of total phosphorus will decrease 24-42%, so it is necessary to compensate sample blank for chroma and muddy sample. In the experiment of doing standard curve, there is no obvious difference whether the distilled water was digestion or not. The best temperature of color reagent stay stable is 15~30C. The experimental results show to allow the color to develop at least 10 minutes but no longer than 30 minutes. The three reducing agent-tin chloride sodium sulfite ascorbic acid are all have their merits and disadvantages, we can select them according to the facts.This experiment concerned ammonia-nitrogen in water with Nessler's reagentcolorimetry. Some results were confirmed after series of experiments. The best dosage ratio of HgCl2 and KI is 2.2:5 confection 100ml Nesslef s reagent. After determination the dilute multiple of filter the waste water sample.we select flocculation-precipitation preprocessing when the number over 10 and selecl the method of distilling sample when the number below 10. The pH should be controlled strictly and move to neutral after dealing with the water sample because it affect the absorbency greatly. The test also show the best time of allowing the color develop is between 15minutes and 60minutes. The optimal environmental temperature is 25C. There is no obvious difference and system error between de-ionized and ammonia-free water in experiment of determination of ammonium, what's more the recovery ratio and accurate and precise were all meet the requirement of test.