【摘要】 <正>1-（5-溴-2-吡啶偶氮）-2,7-萘二酚（5-Br-PADN）属于吡啶偶氮类显色剂。它与PAN相比较,在吡啶环上引入了一个吸电子基—溴原子,萘环上增加了一个给电子基团—酚羟基。由于两者的电子效应,使该显色剂分子共轭体系内电子的活化能降低,加之,它们的助色效应和加重效应的影响,希望其灵敏度和选择性较PAN有所改善。 作者自合成5-Br-PADN以来,已应用于钴、镍、铜的测定。最近,又研究了在阳离子表面活性剂溴化十六烷基三甲基铵（CTMAB）的存在下,5-Br-PADN与锌的显色反应。试验结果表明。在pH10.5的硼砂介质中,它与锌形成紫红色的络合物,其组成为:Zn:R=1:2。络合物的且_max为550nm,表观摩尔吸光系数为5.25×10⁴。更多还原

【Abstract】 In this paper,the color reaction of Zinc ( II ) with 1-[ ( 5-bromo-2-pyridyl ) azo]-2, 7-dihydroxylna phthalene ( 5-Br-pADN ) is studied in the presence of cationic surfactant CTMAB. In Na2B4O7 buf-ier solution of pH 10. 5, 5-Br-PADN combines with zinc to form red-violet complex which shows an maximum absorption at 550nm with molar absorptivity of 5. 25×104. The composition ratio of Zn-5-Br PADN is 1 : 2, Beer’s law is obeyed in the range of 0-30μg/2Sml for Zinc. Using the 5-Br-PADN-CTMA system to determine Zinc in practical samples, satisfactory results are obtained.更多还原