Shen ChangHong
To be a supplier of high quality
laboratory analytical instruments in China.
Shen ChangHong
To be a supplier of high quality
laboratory analytical instruments in China.
There are many kinds of organics in water, so it is difficult to measure the quantitative values of various components one by one. At present, the oxygen demand equivalent to the organics in water is often measured to indirectly characterize the content of organics (such as cod, BOD, etc.), or a certain kind of organic pollutants (such as phenols, oils, benzenes, organophosphorus pesticides, etc.). However, the above indicators can not accurately reflect the situation and harm of many trace harmful organic pollutants. Therefore, with the development of environmental scientific research and analytical testing technology, the monitoring and control of toxic organic pollutants will be greatly strengthened.
Measurements of total nitrogen. Ultraviolet method: this method can measure the content of total nitrogen in surface water, domestic sewage and industrial wastewater. Measurement principle: inorganic nitrogen and organic nitrogen in water are oxidized and digested by potassium persulfate and then converted into nitrates. In the medium of sulfuric acid and phosphoric acid, nitrates react with 2,6-xylenol to form 4-nitro-2,6-xylenol and develop color.
Ammonium molybdate method was used to measure total phosphorus in water. Under neutral condition, potassium persulfate was used to digest the water sample and convert the phosphorus contained into orthophosphate. In the acid medium, orthophosphate reacts with ammonium molybdate to form phosphomolybdic heteropoly acid in the presence of antimony salt, which is immediately reduced by ascorbic acid to form a blue complex, and the color is compared at the wavelength of 700nm.
The Nessler's colorimetry is used to measure the ammonia nitrogen in the water by the ammonia nitrogen analyzer. The method has the characteristics of simple operation and high sensitivity. The principle is that the ammonia nitrogen in the form of free ammonia or ammonium ion reacts with sodium reagent to form a yellow brown complex, and the chroma of the complex is directly proportional to the content of ammonia nitrogen. What are the precautions for measuring ammonia nitrogen with the ammonia nitrogen tester?
The performance of water quality analysis instruments in the Chinese market is far better than that in the past few years, and it is expected to grow rapidly in the next five years. The main reasons for the growth of analytical instruments in China include the booming pharmaceutical industry and the emphasis on sewage treatment; the rising demand for water and the aggravation of water pollution drive the demand for water quality analytical instruments in China.
According to different test standards, ammonia nitrogen tester has a and B types. Among them, type A uses Nessler's Reagent Colorimetry gb7479-87; type B uses salicylic acid photometry as the basic test method in accordance with national standard gb7148-81 and international iso7150 / 1-1948, supplemented by sample colorimetric reaction pretreatment, to achieve rapid and accurate colorimetric determination of samples, which has the advantages of stability, sensitivity, reliability and mercury free.
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