二溴羟基苯基荧光酮分光光度测定微量铋

Spectrophotometric Determination of Micro Amounts of Bismuth with 2,6,7-Trihydroxy-9-(3,5-dibromo-4-hydroxy) Phenylfluorone-3

研究了新显色剂二溴羟基苯基荧光酮（ＤＢＨＰＦ）在阳离子表面活性剂溴化十六烷基三甲基铵（ＣＴＭＡＢ）存在下与铋的显色反应。在ｐＨ６．４～６．７的六次甲基四胺─盐酸缓冲介质中，Ｂｉ（Ⅲ）与ＤＢＨＰＦ反应生成组成比为１：２的水溶性和稳定性皆佳的紫蓝色络合物，其吸收峰波长λｍａｘ＝６０２ｎｍ，对比度（△λ＝８２ｎｍ表现摩尔吸光系数ε６０２＝５．３６×１０４Ｌ·ｍｏｌ－１·ｃｍ－１。Ｓａｎｄｅｌｌ灵敏度是３．９０×１０－３μｇ·ｃｍ－２，Ｂｉ（Ⅲ）浓度为０～１５．０μｇ／１０ｍｌ时服从比尔定律，其检测下限是０．２１μｇ／１０ｍｌ。采用巯基棉分离，能够消除许多金属离子的干扰。本方法用于焊锡和铸造锡合金中微量铋的测定，结果较满意。

The colour reaction of bismuth(Ⅲ) with 2,6, 7-trihydroxy-9-(3,5-dibromo-4-hydroxy)-phenylfluorone-3(DBHPF) and cetyltrimethylammonium bromide(CTMAB) has been studied.In the(CH2) 6N4-HCl buffer medium at PH6.4-6.7,the complex formed has a maximum absorption at 602nm,and its apparent molar absorptivity is 5.36×104L·mol-1·cm-1,Sandell sensitivity is 3.90×10-3μg·cm-2.The molar ratio of Bi(Ⅲ) to DBHPF in the complex is estimated to be 1:2.The calibration curve is linear up to 15.0μg Bi per 10ml,and the detection limit is 0.21μg Bi per 10ml.The effect of other metal ions has also been investigated.The method has been satisfactorily applied to the determination of Bi in some alloys after the interferential ions have been separated with sulfhydryl fiber cotton.