氧化胺基苯磺酸黄褪色光度法测定食盐中碘

Spectrophotometric Detemination of Iodine in Salt by Decoloration of Metanilic Acid Yellow Oxidized by Iodate

在稀H2 SO4 -KBr介质中 ,KIO3氧化胺基苯磺酸黄 (NaSO3·C6 H4 ·N :N·C6 H4 ·NH·C6 H5)褪色 ,褪色的程序与碘的存在量之间有良好的线性关系 ,借此建立了测定碘的新分光光度法 .有色溶渡的最大吸收波长为 5 2 8mm ,碘量在 0～ 5 0ug 2 5ml范围内符合比耳定律 ,表观摩尔吸光系数ε=4 .4 8× 10 4 L·mol- 1 ·cm- 1 .该法简便、准确 ,有色溶液稳定 ,用于食盐中碘的测定 ,结果满意 .

A new spectrophotometric method for the determination of iodine in salt was investigated. Themethod is based on the decoloring reaction of Metanilic acid yellow oxidized by iodate in the medium of H 2SO 4-KBr. The maximum absorption of colored solution is at 528 mm. Beer's law is obeyed from 0 to 50 ug/25 ml of iodine. The colored solution is very stable. The apparent molar absorpivity is 4.48×10 4L·mol -1·cm -1.This method is simple, accuracy. The method has been applied to the deterination of iodine in sale with satisfactory results.