Principle of chemical reaction
1. Nitrite
In the acid ethanol system, nitrite ions were converted into NO2 gas and determined at 213.9nm.
H++NO2-+CH3CH2OH→ NO2↑
2. Ammonia nitrogen
First
use the hypobromite oxidation to nitrite, and then according to the method for
the determination of nitrite.
NH3-N+[O] → NO2-—N；
H++NO2-+CH3CH2OH→ NO2↑
3.Kjeldahl nitrogen
The
sample was converted into ammonium hydrogen sulfate solution after the digestion
of sulfuric acid and mercury salt at high temperature, and the method was
directly determined by ammonia nitrogen determination method.
4. Nitrate
Under
heating, titanium trichloride reduction nitrate ion for NO gas, 214.4nm
wavelength
NO3-+TiCl3 →NO↑
5.Total nitrogen
After the sample was digested with alkaline potassium persulfate, all nitrogen compounds were converted into nitrate, and the nitrate was directly determined by the method of determination.
6.Sulfide
The
sample after adding acid, sulfide into H2S gas, 202.6nm determination.
H++[S]2- →H2S↑
