双硫腙-乙醇体系分光光度法测锌的研究

Determination of zinc by the spectrophotometric method of dithizone

摘要: 探讨了在表面活性剂作用下 ,用双硫腙 -乙醇体系分光光度法测定样品中微量锌的条件及应用 .实验结果表明 :在 p H6.5～ 6.8的溶液中加入掩蔽剂 ,在有表面活性剂溴化十六烷基三甲胺 ( CTMAB)的存在下 ,锌 ( II)与双硫腙形成稳定的紫红色络合物 ,其络合比为 1∶ 2 ,最大吸收波长为 5 90 nm,表观摩尔吸光系数为 9.2 2× 1 0 4 L· mol- 1 · cm- 1 ,锌含量在 7.5～ 3 0μg/ 5 0 m L范围内服从比耳定律 .此法操作简便 ,显色稳定 ,灵敏度高 ,选择性好 ,可用于水样中锌的测定 ,回收率在 97.0 %～ 1 0 0 .7%之间

Abstract: The determination of zinc with the color reaction of dithizone and ethanol was investigated in the presence of surfactant.The results show that dithizone and zinc can form a stable red complex at 590 nm in the presence of cetyltrimethylammonium bromide.The molar ration of Zn(Ⅱ)to dithizone in the complex is etimated to be 1∶2. The apparent molar absorptivity is 9.22×10~4 L·moL~(-1)·cm~(-1) at 590 nm. Beer's law is obeyed in the zinc concentration range of 7.5～3.0 μg/50mL.This proposed method can...