2,6-二溴-4-甲基偶氮磺与铅显色反应的研究与应用

STUDY ON THE COLOR REACTION OF 2,6-DIBROMO-4-METHYL-SULFONAZO WITH LEAD AND APPLICATION

了２，６－二溴－４－甲基偶氮磺（ＤＢＭ－ＳＡ）与铅的显色反应，在０．６ｍｏｌ／ＬＨ３ＰＯ４介质中，铅与ＤＢＭ－ＳＡ发生灵敏的显色反应，生成稳定的蓝色配合物， 组成为Ｐｂ（Ⅱ）：ＤＢＭ－ＳＡ＝１：２，最大吸收波长在６４２ｎｍ，表观摩尔吸光系数达９．２×１０＾４，铅的浓度在０￣２０μｇ／２５ｍＬ之间服从比尔定律，可以允许大量的金属离子（除钙外）共存。进一步研究发现，结合ＫＪ－ＭＩＢＫ萃取法。

A new reagent dibromo-p-methyl-sulfonazo (DBM-SA) was studied as a sensitive and high selective chromogenic reagent for lead in this paper.In 0.6 mol/L H3PO4 medium,DBM-SA reacts with Pb( II ) to form a stable 1:2 blue chelate,the absorption maximum of this chelate lies at 642 nm with an apparent molar absorptivity of 9.2×104.Beer's law is obeyed in the range over 0 ~ 20μg Pb2+/25 mL.Relatively large amounts of co-existing elements including transition metals can be permitted.The proposed method has been applied to the determination of lead in environmental samples.