The method describes how to determine the iron content of water photometrically with a cuvette test.
Iron(II) ions form a rust-colored complex with 1,10-phenanthroline. Iron(III) ions are reduced to iron(II) ions.
The method describes how to determine the manganese content of water photometrically with a cuvette test.
Manganese(II) ions react in an ammonia solution with formaldoxime, forming a reddish-colored complex.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
Ammonium ions react at a pH of approx. 12.6 with hypochlorite ions and salicylate ions in the presence of sodium nitroprusside, which serves to catalyze the reaction, to form a green color (indophenol blue).
The method describes how to determine the sulfate content of water by means of a photometric cuvette test.
In the presence of barium chloride, sulfate ions form barium sulfate, which is only slightly soluble in water. The turbidity produced by doing so is determined with a photometer.
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 nitrate content of water photometrically with a cuvette test.
In an acidic sulfurous solution containing phosphorus, nitrate ions react with 2,6-dimethylphenol to produce 4-nitro-2,6-dimethylphenol.
The method is suitable for determining approx. 0.5–25 mg/l NO3-. If the ratio of chloride to nitrate ions is larger than 10, this may interfere with the reaction (if this is the case, according to DEV D 9-3, follow DIN 38405); likewise, nitrite ions exceeding approx. 0.2 mg/l may also interfere with the reaction. For their removal, refer to Remarks below.