【摘要】 <正> 曾有人研究了数种吡啶偶氮类化合物与铋的显色反应,用于络合滴定时的金属离子指示剂和萃取光度法的显色剂。本文研究了另一种吡啶偶氮化合物2-（3,5-二溴-2-吡啶偶氮）-5-二甲氨基苯酚（简称3,5-Br₂-DMPAP）与铋的显色反应。在Tween-80存在下,水相显色,具有较高的灵敏度且显色速度快、稳定时间长。用邻菲啰啉作掩蔽剂使该反应具有较好的选择性,采用巯基棉进行分离可用于铜、锌等有色金属中微量铋（0.00X％）的测定。更多还原

【Abstract】 In the presence of Tween-80, a blue complex of bismuth with 3,5-Br₂-DMPAP is formed imediately at pH 2 in the composition ratio of 1:1. Its maximum absorbance is measured at 600 nm, and the molar absorptivity is 8.0×10⁴l·mol_-1·cm_-1. Beer’s law is obeyed for solutions containing 0—10μg/25ml bismuth. The sulfhydryl-cotton has been used to separate Bi （Ⅲ） from copper and other elements. This method has been used in the determination of Bi in brass and pure zinc.更多还原