The method describes how to determine the nitrite content of water photometrically with a cuvette test.
In an acidic solution, nitrite reacts with primary aromatic amines, producing diazonium salts. Together with aromatic compounds, they form azo compounds, which contain an amino or hydroxyl group and exhibit an intense color.
The method describes how to determine the chloride content in water by means of the analytical method according to MOHR.
Transformation of the chloride ions in the presence of silver ions produces silver chloride, which is not very soluble, until all the chloride ions are bound. The excess silver ions react with chromate ions to silver chromate, which exhibits a reddish brown color:
Cl - + Ag+ → AgCI
2 Ag+ + CrO42- → Ag2CrO4
The method describes how to determine the chlorine dioxide content of water photometrically with a cuvette test.
Transformation of chloride solutions in the presence of mercury thiocyanate produces less-dissociated mercury(I) chloride. An equivalent quantity of thiocyanate ions is released simultaneously, forming iron(III) thiocyanate with iron(III) salts. The red hue resulting from the reaction is determined photometrically.
The method describes how to determine the anion content of water by means of ion chromatography.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
Separation using ion chromatography and subsequent conductivity detection (of other anions as well)
The method describes how to determine the free and total chlorine content using a titrimetric method with DPD.
The analysis involves a reaction with N,N-diethyl-1,4-phenylenediamine (DPD), which forms a compound possessing a red color at a pH of 6.2–6.5. The solution is titrated with an ammonium iron(II) sulfate standard solution until the red color disappears. Total chlorine is measured through the addition of potassium iodide, of which a known amount in excess of that required is added to the solution in advance.
The method describes how to determine the total chlorine content of water using an iodometric method.
The total chlorine reacts with potassium iodide in an acidic solution, releasing free iodine. Immediate reduction of the iodine is performed using a thiosulfate standard solution, of which a known amount in excess of that required was added to the solution in advance. The thiosulfate left untransformed is titrated using a potassium iodate standard reference solution to complete the analysis.