7－（苯偶氮）－8－羟基喹啉－5－磺酸钠光度法测定铝

Spectropkotometric determination of Al(Ⅲ)with 7-(benzeneazo)-8-hydrolyquinoline-5-sulfonic acid

研究了７－（苯偶氮）－８－羟基喹啉－５－磺酸钠光度法测定铝（Ⅲ）的实验条件及反应机理。该显色剂在ｐＨ４．２水溶液中呈红色，λｍａｘ＝５２０ｎｍ，与铝（Ⅲ）形成配合物后呈黄色。其配合比为１：３，最大吸收峰为λｍａｘ＝４３５ｎｍ。测得摩尔吸光系数ε４３５＝１．６７×１０４Ｌ·ｍｏｌ－１·ｃｍ－１。该方法灵敏度好，在０．００～８．００μｇ／１０ｍＬ范围内符合比尔定律，方法简便，稳定性好。用于钢中铝的测定结果满意。

In this paper, the reaction conditions of spectrophotometric determination of Al(Ⅲ)with 7-(benzeneazo)-8-hydroxyquinoline-5-sulfonic acid were studied.Primary colour of the reagent is red in a solutionof pH 4.2 (λmax=520nm), but yellow when itreacts with Al(Ⅲ) to form a complex. The complexratio is 1:3, λmax=435nm. Its molar absorptivity is 1.67×104L·mol-1, cm-1 Beer′s law is obeyed from 0.00～8.00μg/10mL. The method is simple and has been applied to the detrmination of aluminum in steel with satisfactory results.