Method for fast detecting concentration of nutrient nitrogen salt in seawater

Abstract

The invention relates to a method for fast detecting concentration of nutrient nitrogen salt in seawater. The method includes the steps of collection and pretreatment of seawater samples, concentration detection of nitrite nitrogen, concentration detection of nitrate nitrogen and concentration detection of ammonia nitrogen. A color developing agent C1, a color developing agent C2 and a color developing agent C3 are all prepared by mixing concentrated hydrochloric acid, sulfanilamide, naphthyl ethylenediamine and water. By mixing the concentrated hydrochloric acid, the sulfanilamide and the naphthyl ethylenediamine to prepare a single color developing agent, the color developing agent only needs to be added once during detection, and then the whole developing process can be completed, so that the operation is simple and fast; moreover, since the color developing agent is colourless and the color and the effects of the color developing agent are stable, the precision of the detection results is ensured; by adopting the single color developing agent, errors caused by gradually darkening color of a naphthyl ethylenediamine solution in a traditional detection method are avoided; according to the method, by adopting a minusing method to detect the concentration of the nitrate nitrogen and the ammonia nitrogen, the operation is convenient and fast. The method for fast detecting the concentration of the nutrient nitrogen salt in the seawater has the advantages of being simple to operate, fast, small in error, capable of saving time and labor, and particularly suitable for fast on-site concentration detection of the nutrient nitrogen salt in the seawater.

Description

technical field [0001] The invention relates to the field of chemical quantitative analysis, in particular to a water quality monitoring technology, in particular to a method for rapidly detecting the concentration of nitrogen nutrient salts in seawater. Background technique [0002] Nitrogen nutrient salt in seawater - nitrite nitrogen (NO 2 - -N), nitrate nitrogen (NO 3 - -N), ammonia nitrogen (NH 4 + -N) (hereinafter referred to as "three nitrogens") is a mandatory inspection item for marine monitoring. There are many methods for determining the concentration of "three nitrogens" in seawater, such as ultraviolet spectrophotometry, ion chromatography, chemiluminescence, flow injection, etc., but these methods have low sensitivity, the instrument is not easy to carry, and it is difficult to measure or operate in real time on site complex issues. [0003] The determination of the concentration of "three nitrogen" in seawater in my country can follow the "GB 17378.4-20...

AI Technical Summary

Problems solved by technology

[0005] In addition, the cadmium column reduction method reduces the nitrate in the water sample to nitrite through the copper-coated cadmium column, which is complicated and cumbersome to operate.

Both the cadmium column reduction method and the hypobromite oxidation method involve pipetting the solution many times, and the operation process is complicated and lengthy, time-consuming and labor-intensive. Especially when the on-site measurement of ocean water is carried out, large automatic instruments are not suitable for use on board, which is cumbersome. The operation cannot adapt to the on-site environment on the ship

Images