Operation process of total nitrogen detector

There are four types of nitrogen in sewage, organic nitrogen, ammonia nitrogen, nitrite nitrogen and nitrate nitrogen. A large amount of domestic sewage, farmland drainage or nitrogen-containing industrial sewage is discharged into the water body, which increases the content of organic nitrogen and various inorganic nitrogen compounds in the water, and the proliferation of organisms and microorganisms consumes dissolved oxygen in the water and deteriorates the quality of the water body. When the total nitrogen content in water is greater than 0.3mg/L, it reaches the eutrophication standard; in addition, nitrate itself is harmless to humans, but it will be reduced to nitrite in the body. On the one hand, nitrite will react with hemoglobin The formation of methemoglobin affects the ability to transport oxygen, especially for infants, which can easily lead to methemoglobinemia (blue baby disease); It is extremely harmful. Total nitrogen is often used to indicate the degree of water pollution by nutrients. It mainly comes from microbial decomposition and industrial emissions. Nitrogen in the air is insoluble in water. Its 'Environmental Protection Law of the People's Republic of China' clearly regulates the water quality total nitrogen standard of industrial wastewater and domestic sewage. How should we detect the total nitrogen content in the water quality? Next, I will introduce the use of the total nitrogen detector! The operation steps are as follows: 1. Turn on the power of the host and preheat for 2 minutes; turn on the power of the digester and select the total nitrogen digestion mode (125°C, 30 minutes); 2. Blank: draw 2ml of distilled water in the colorimetric tube; (need to add reagents and digestion) (1) When the total nitrogen value of the sample is 0-20mg/L (total nitrogen L), draw 2ml of the sample into another colorimetric tube; (2) The total nitrogen value of the sample is 20-100mg/L (total nitrogen H) draw 0.4ml water sample into another colorimetric tube, then add 1.6ml distilled water; (or take 2ml after diluting 5 times) 3. Add 1ml total nitrogen reagent respectively (1) , cover and shake well, and put it in a heated digester for digestion. After the digestion is completed, take it out and cool it; 4. After cooling, add 0.5ml total nitrogen reagent (2), cover it and shake it well; 5. Take another same For a number of empty colorimetric tubes (including blanks), first add 0.8ml total nitrogen reagent (3) concentrated solution, then add 3.2mL (10+1) sulfuric acid, then add 1ml of the previous digestion solution, cover and shake well, let Set it aside for 10 minutes; 6. Wipe the colorimetric tube clean, perform a blank measurement under the corresponding item first, and then perform a sample measurement, and the displayed value is the concentration value. 7. After the measurement is completed, clean the colorimetric tube and dry it. Note: 1. The built-in working curve can directly measure the water sample; 2. When measuring, the water sample can be roughly predicted first, and the over-range dilution sampling is measured; 3. When using a glass pipette to measure/add samples and reagents The pipette should be measured with a horizontal view of the concave liquid; 4. The pipettes (pipette tips) for pipetting samples/reagents should not be used interchangeably to prevent reagent contamination; 5. If the sample contains nitrate nitrogen, the color should be Brownish yellow, and the higher the concentration, the darker the color; 6. Insert the blank digestion tube into the colorimetric tank for about 2-3 seconds and then press 'Confirm' after the reading is stable;