A method of measuring the ammonia nitrogen concentration of a water body

Abstract

The invention belongs to the technical field of water quality monitoring, and relates to a method of measuring the ammonia nitrogen concentration of a water body. The method includes a step of preparatory work, a step of mapping an ammonia nitrogen standard curve, a step of mapping nitrite nitrogen standard curve, a step of mapping a curve of influences of nitrite nitrogen concentrations on ammonia nitrogen measurement absolute errors and a step of measuring the ammonia nitrogen concentration, which are five steps. Wider-range ammonia nitrogen and nitrite nitrogen concentrations in a high-salinity water body can be measured. Hypobromite oxidation time is shortened from 30 min to 10 min. Hydrochloric acid is adopted in place of phosphoric acid for a nitrite nitrogen color developing agent, thus reducing pollution. A hydrochloric acid solution of sulfanilamide and an aqueous solution of N-(1-naphthyl)ethylenediamine dihydrochloride are mixed, and therefore nitrite nitrogen concentration measuring steps are simplified. The upper limit of nitrite nitrogen concentration measurement is increased to a value that is three or more times of the upper limit in the national standard method in China. In a nitrite nitrogen concentration range of 0-0.75 mg/L, accuracy of measurement of ammonia nitrogen concentrations in a range of 0-1.25 mg/L is good. The method has characteristics of a simple process, reliable principles, short operation time, environment protection, energy conservation, a low economic cost, high operationality and high measurement result accuracy.

Description

[0001] Technical field: [0002] The invention belongs to the technical field of water quality monitoring, and in particular relates to a method for measuring the ammonia nitrogen value in a water body. On the premise of eliminating the interference of nitrite nitrogen (nitrite nitrogen), the upper limit value for the determination of the ammonia nitrogen concentration in the water body is improved, and at the same time the The upper limit of the determination of nitrite nitrogen concentration is used in water purification, aquatic animal and plant cultivation and breeding and other occasions. [0003] Background technique: [0004] Ammonia nitrogen refers to the free ammonia (NH 3 ) and ammonium ions (NH 4 +) The nitrogen in the form of nitrogen mainly comes from the decomposition of organic nitrogen and the reduction of nitrate nitrogen and nitrite nitrogen. Ammonia nitrogen has a great impact on human health and the ecological environment: ammonia nitrogen in water is conve...

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Problems solved by technology

[0004] Ammonia nitrogen refers to the free ammonia (NH 3 ) and ammonium ions (NH 4 +) The nitrogen in the form of nitrogen mainly comes from the decomposition of organic nitrogen and the reduction of nitrate nitrogen and nitrite nitrogen. Ammonia nitrogen has a great impact on human health and the ecological environment: ammonia nitrogen in water is converted into nitrite under certain conditions. Drinking, nitrite will combine with protein to form strong carcinogenic nitrosamines, which is extremely harmful to human health; the harm of ammonia nitrogen to aquatic organisms mainly includes reduced food intake, slowed growth, tissue damage, reduced oxygen transport between tissues, It can lead to hyperactivity of aquatic organisms, loss of balance in the water, convulsions, and even death in severe cases. The fish among them are sensitive to ammonia nitrogen. When the ammonia nitrogen content is high, the fish will die; ammonia nitrogen is very polluting to the marine environment. Can not be ignored; Therefore, the ammonia nitrogen concentration value is one of the important water quality monitoring indicators of close attention in aquaculture nursery and culture, and the mensuration of the ammonia nitrogen concentration in the mariculture water body is the important foundation of mariculture production management and scientific research work; In the prior art, The methods for determining the concentration of ammonia nitrogen mainly include Nessler's reagent colorimetric method, ion chromatography, gas phase molecular absorption method, indophenol blue spectrophotometry and hypobromite oxidation method, wherein Nessler's reagent colorimetric method utilizes mercuric iodide and The alkaline solution of potassium iodide reacts with ammonia to form a light reddish brown colloidal compound. The chromaticity is proportional to the concentration of ammonia nitrogen. The concentration of ammonia nitrogen is calculated after measuring the absorbance in the wavelength range of 410-425nm. However, due to the large amount of calcium and Magnesium ions, while calcium and magnesium ...

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