退色光度法测定锰的研究

Study of Decolored Spectrophotometric Determination of Manganese

研究了在Ｈ２ＳＯ４介质中，甲基橙被Ｍｎ（Ⅶ）氧化并退色而测定锰的新方法．其退色程度与Ｍｎ（Ⅶ）的浓度成线性关系，Ｍｎ（Ⅶ）含量在０～０．８μｇ／ｍＬ范围内服从比耳定律，有色溶液的最大吸收波长为５１０ｎｍ，表观摩尔吸光系数为４．０×１０４Ｌ·ｍｏｌ－１·ｃｍ－１，该方法简单、快速、准确，选择性好．用于矿样中锰的测定。

A new method has been studied in this paper for the determination of manganese. It is based on decoloration of oxidation of methyl orange by Mn(Ⅶ) in H 2SO 4 medium. The decrease in colour is directly proportional to concentration of manganese. Beer′s law is obeyed from 0 to 0.8 μg/mL of Mn(Ⅶ). The wave length of maximum absorption of colored solution is 510 nm and the apparent molar absorptivity is 4.0×10 4 L·mol -1 ·cm -1 . The method is simple, quick, accurate and has high selectivity. The method has been applied to the determination of manganese in mineral samples. The results are satisfactory.