The method is applicable to all waters containing between 0.01 and 0.25 mg of nitrous nitrogen per liter or brought to this concentration by dilution. The method may not be applicable in the presence of antimony, bis uth, lead, mercury (II) and metavanadate ions due to the formation of a precipitate. Iron (III) does not interfere up to a concentration of 20 mg/1. Nitrogen trichloride produces a reddis color which could be confused with that produced by nitrites. However, due to chemical incompatibility, it is unlikely that nitrites will survive in the presence of nitrogen trichloride or free chlorine.
NBN T 91-257-1977 history
1977NBN T 91-257-1977 Water analysis methods - Determination of the nitrite nitrogen - Photoraetric method