Total nitrogen
Definition of total nitrogen
Total nitrogen, referred to as TN, the total nitrogen content in water is one of the important indicators for measuring water quality. Total nitrogen is defined as the total amount of various forms of inorganic and organic nitrogen in water. Including inorganic nitrogen such as NO3-, NO2- and NH4+ and organic nitrogen such as protein, amino acids and organic amines, calculated in milligrams of nitrogen per liter of water. It is often used to indicate the degree of nutrient pollution of water bodies.
Total nitrogen monitoring purpose
The total nitrogen content in water is one of the important indicators for measuring water quality. Its measurement helps to evaluate the pollution and self-purification status of water bodies. When nitrogen and phosphorus substances in surface water exceed standards, microorganisms multiply, plankton grows vigorously, and eutrophication occurs.
Total nitrogen detection method
The main methods for measuring total nitrogen in water quality are:
Alkaline potassium persulfate UV spectrophotometry (HJ 636-2012):
Nowadays, the main method of water quality monitoring, such as British RAIKING, Chinese Ruiquan and other brands are mainstream online monitoring products optimized on the basis of this standard.
Gas-phase molecular absorption spectrometry
This method is mainly used in laboratories.
Measure total nitrogen using ammonia nitrogen, nitrate, and nitrite
Measure total nitrogen using ammonia nitrogen, nitrate, and nitrite, and then use the cumulative value as the measurement result of total nitrogen. Typical applications include German WTW.
In the field of environmental surface water and water quality monitoring, alkaline potassium persulfate UV spectrophotometry and optimization methods are currently the main methods.