催化褪色分光光度法测定牛奶中微量锌

Determination of trace zinc by catalysis discoloration spectrophometry

目的：建立测定牛奶中微量元素锌的分光光度方法。方法：在H2SO4介质中,微量锌对过氧化氢氧化二甲酚橙的反应体系具有催化作用,且二甲酚橙被氧化后的褪色程度ΔA与微量锌的含量有线性关系,据此建立了二甲酚橙褪色光度法测定微量锌的新方法。结果：本法的最大吸收波长为690 nm,表观摩尔系数为1.52×10^4L/moL·cm,线性范围为0～5.2μg/m l,最低检出限为0.13μg/m l,相对标准偏差为1.2%～6.0%,测定结果与标准方法差异无显著。结论：该方法操作简单,线性范围大,准确度好,可用于实际样品的测定。

Objective： To establish a method to determine the components of microdement in the milk with spectrphotometry. Methods：Zinc has catalysis ability in the system of oxidze xylenol orange in medium, and the discoloration extent of methyl orange has a linearity to the content of zinc. Based on this fact, a new photometric method for the determination of zinc was proposed. Results：The absorptive maximum was 690 nm, with an apparent molar absorption of 1.52 × 10^4 L/moL · cm. Beer＇s law was obsorptive maximum in the concentration range from 0 to 5.2 μg/ml. The detection limit of this method was 0. 13 μg/ml and the relative standard deviation 1.2% - 6.0%. Conclusion：This method was simple and accurate.