2-(2-噻吩偶氮)-5-二乙氨基酚近红外分光光度法测定铁(Ⅱ)

Near infrared spectrophotometry of iron(Ⅱ) with 2(2thienylazo)5diethylaminophenol

在ｐＨ９５～９８的碱性介质中，２（２噻吩偶氮）５二乙氨基酚能与铁（Ⅱ）形成最大吸收波长位于近红外区７５８ｎｍ的螯合物．由于在该波长下其他离子的螯合物均无吸收而获得极高的选择性，显色反应有较高的灵敏度，摩尔吸光系数为３６１×１０４Ｌ·ｍｏｌ－１·ｃｍ－１．该方法可用于铝合金中铁的直接、快速测定．

 near infrared spectrophotometric method of iron(Ⅱ) has been reported. In the medium of pH9 5～9 8, iron(Ⅱ) reacts with 2(2thienylazo)5diethylaminophenol(TADAP) to form a complex with the maximum absorption peak being at 758nm. As complexes of other ions do not absorb in this region, the colour reaction has very good selectivity and has higher sensitivity ( ε =3 61×10 4L·mol -1 ·cm -1 ). This method has been applied to the direct and rapid determination of iron in aluminum alloys with satisfactory results.