吐温-80-DDTC胶束增溶吸光光度法测定饮料中微量铜

MICELLAR SOLUBILIZATION PHOTOMETRIC DETERMINATION OF MICROAMOUNTS OF COPPER IN DRINKS WITH DDTC IN THE PRESENCE OF TWEEN 80

利用非离子表面活性剂的胶束增溶增敏作用，研究和建立了吐温-80-DDTC水相体系中直接测定饮料中Cu（Ⅱ）的方法。在表面活性剂吐温-80存在下，于pH10．0碱性介质中，Cu（Ⅱ）与铜试剂（DDTC）形成灵敏度高的棕黄色络合物。铜含量在0．028～4．70mg·L^-1范围内遵守比耳定律，表观摩尔吸光系数为1．32×10^3L·mol^-1·cm^-1，检出限为0．01mg·L^-1，相对标准偏差为1．04％～1．67％，回收率为96．1％～101．7％，测定结果与有机溶剂萃取法一致。

In an ammoniacal buffer of pH 10, the coordination reaction of Cu（ Ⅱ ） with DDTC was solubilized by the addition of Tween 80, and the photometric measurements were made directly in the aqueous solution at the wavelength of 442 nm. Where the apparent molar absorptivity was found to be 1.32×10^3L · mol^-1 · cm^-1. Beer＇s law was obeyed in the concentration range of 0. 028-4. 70 mg of Cu per L of solution, with a detection limit of 0. 01 mg · L^-1. This method has been used in the determination of copper in 5 kinds of drink samples, giving RSD＇s in the range of 1.04%-1.63% and recoveries in the range of 96. 5%-101.7%. And also the results obtained by this method were in consistency with those found by the DDTC-CCl4 extraction photometric method.