Spectrophotometric determination of nitrite with 4-iodo-N,N-dimethylaniline

The nitrosation reaction of p-halogen derivatives of N,N-dimethylaniline was considered. It was discovered that the behaviour of 4-iodo-N,N-dimethylaniline (IDAN) in this reaction essentially differs from that of analogues. During its interaction with nitrite an intensively coloured substance is formed. For this reason IDAN was studied as a possible reagent for nitrite determination. The investigations showed that it surpasses the best known analogues with regard to analytical properties, so a method of nitrite determination in natural and waste water was worked out. The method is rapid (15 min), one-stage, non-sensitive to most admixtures and has a low detection limit (2 μg/l nitrite nitrogen). The reagent is suitable for the flow-injection determination of nitrite and nitrate.