丁基罗丹明B氧化褪色光度法测定食盐中的碘含量

Spectrophotometric Determination of Iodine in Table Salt by Oxidation-Decoloration of Butyl Rhodamine B

关键词:  碘  食盐  丁基罗丹明B  氧化褪色  分光光度法

Key words:  iodine  table salt  butyl rhodamine B  oxidation-decoloration  spectrophotometry

摘要:

在H₂SO₄介质中,KBr存在下,碘酸根氧化丁基罗丹明B使之褪色,褪色程度与碘酸根的量有关,据此建立了褪色光度法测定碘的新方法。新方法用于测定加碘食盐中碘含量的最大吸收波长为560nm,碘浓度在0~400μg/L范围内与丁基罗丹明B褪色程度呈线性关系,表观摩尔吸光系数ε₅₆₀=9.27×10⁴L·mol^-1·cm^-1。新方法的灵敏度高,室温可以进行反应,操作简便,用于加碘食盐中碘含量测定的结果令人满意。

Abstract:

A new sensitive method has been developed for the determination of iodine by oxidation-decoloration of butyl rhodamine B.The colour system has a maximum absorption at 560nm in the medium of H₂SO₄-KBr with a molar absorptivity of 9.27×10⁴L·mol^-1·cm^-1.Beer's law is obeyed in the range of 0~400μg/L of iodine.The method has been applied to the determination of iodine in table salt with satisfactory results.