树脂相分光光度法测定水中微量铁(Ⅲ)

Spectrophotometric Determination of Trace Fe(Ⅲ) in Water with Resin Adsorption

在ｐＨ６６０的弱酸性介质中，焦性没食子酸与铁（Ⅲ）生成有色络阴离子，与强碱性阴离子交换树脂交换，将有色配合物富集于树脂相上，用树脂相分光光度法测定微量铁（Ⅲ）。其最大吸收波长位于５００ｎｍ；表观摩尔吸光系数ε为４３×１０４Ｌ·ｍｏｌ－１·ｃｍ－１；铁（Ⅲ）含量在０～２．０ｍｇ·ｌ－１范围内符合比耳定律；用该法测定了内蒙古武川县地下水中微量铁（Ⅲ），结果令人满意。

In pH6.60 weak acid solution,pyrogallic acid forms a colour complex with Fe(Ⅲ), which can be quantitatively adsorbed on anion exchange resin. The maximum absorption wavelength of the resin phase was determined spectrophotometrically to be 500nm. The molar absorptivity is 4.3×10 4L·mol -1 ·cm -1 . Beer′s law is obeyed for Fe(Ⅲ) in the rang of 0～2.0mg·L -1 . The method has been applied to the determination of trace Fe(Ⅲ) of ground water in Wu cuan county, Huhehote with satisfactory.