Total nitrogen (TN) refers to the nitrogen content in soluble and suspended particles in water, including nitrite nitrogen, nitrate nitrogen, inorganic ammonium salts, dissolved ammonia, and nitrogen in most organic nitrogen-containing compounds. When lakes and reservoirs contain excessive nitrogen and phosphorus substances, it causes vigorous reproduction of phytoplankton and leads to eutrophication. Total nitrogen is one of the important indicators for controlling water quality.

In aqueous solutions above 60 ℃, potassium persulfate can decompose to produce potassium bisulfate and atomic oxygen. Potassium bisulfate dissociates in the solution to produce hydrogen ions, so the decomposition process can be promoted to complete in an alkaline medium of sodium hydroxide. The decomposed atomic oxygen can convert nitrogen containing compounds in water samples into nitrates at 120-124 ℃, and during this process, organic matter is simultaneously oxidized and decomposed. UV spectrophotometry can be used to measure the absorbance A220 and A275 at wavelengths of 220nm and 275nm, respectively. The corrected absorbance can be calculated according to the formula A=A220-2A275, and the concentration of total nitrogen in the water sample can be calculated based on the absorbance.

1. High reliability, strong anti-interference ability, suitable for harsh working environments;

2. Intelligent fault self diagnosis function, convenient instrument management and maintenance;

3. Power off protection design, with automatic data recovery function for power off and power on again;

4. Over limit alarm, used in conjunction with a sampler to achieve over limit sample retention;

5. Network connectivity enables data sharing and remote control;

6. Suitable for measuring pollution sources and surface water, as well as for detection in sewage treatment processes;

7. Sequential injection analysis method, simple flow path, low reagent consumption, and high degree of automation;

8. Adopting multi-channel valves, it has strong anti-corrosion performance, long service life, and is safe and reliable.