ammonia nitrogen and total nitrogen measurement method.

organic nitrogen. If the organic nitrogen under the condition of aerobic biological oxidation can be gradually decomposed into NH3, NH4, NO2-, NO3-and other forms, NH3 and NH4 called ammonia nitrogen, NO2-called ammonia nitrite, NO3-called nitrate nitrogen. The content of these forms can be used as water quality indicators, representing the different stages of organic nitrogen conversion to inorganic substances.nitrogen (TN) is a water quality indicator that includes everything from organic ammonia to nitrate nitrogen.In water quality monitoring, the content of the above-mentioned nitrogen-containing organic and inorganic substances is calculated by converting them into mg/l of nitrogen (N2), which is called organic nitrogen, ammonia nitrogen, nitrate nitrogen and total nitrogen.

Ammonia nitrogen was measured by spectrophotometry or ammonia gas sensitive electrode method. The measurement principle of spectrophotometric method on-line ammonia nitrogen analyzer is that in the presence of sodium dichloroisofluorurate, ammonium ions react with sodium salicylate to generate blue compounds, which have the most absorption at the wavelength of 660nm and can be measured by spectrophotometry. In order to prevent the interference of the turbidity of the water sample, the measuring light is compared with a scattered reference light with a wavelength of 880nm. The ammonia gas sensitive electrode method can be found in the ion selective electrode section of the car book.

total nitrogen mainly uses ultraviolet absorption method and chemiluminescence method. The ultraviolet absorption method is based on the national standard GB 11894-89, that is, nitrogen-containing compounds are decomposed and oxidized to NO3-by potassium persulfate, and total nitrogen is measured by ultraviolet method. It is worth noting that this method is susceptible to the interference of bromide ions. The chemiluminescence method has no interference and is considered to be the preferred method for automatic on-line monitoring. The carrier gas brings the water sample into the reaction tube equipped with the catalyst, oxidizes the nitrogen-containing compound to NO through high temperature (700 ~ 950oC) low temperature closed combustion, and then reacts with O3 produced by the ozone generator to measure the chemiluminescence intensity emitted.