The Determination of Trace Iodate(V) by P-nitroaniline and α-Naphthylamine Spectrophotometric Method

A new spectrophotometric method for the determination of iodate (V) has been developed. In HCl medium, iodate(V) oxidizes hydroxylammonium chloride to form nitrite, which can produce a red azo dye with the reaction of p nitroaniline and α naphthylamine. Beer's law is obeyed in the range of 0-2.8×10 -3 g/L with the absorptivity being e 510 =3.918×10 4 L·mol -1 ·cm -1 and the linear relational coefficient being γ =0.999 7. The proposed method has been applied to the determination of iodate (V) in iodized salt samples with satisfactory results.