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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1.52×104L/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 spectrophotometric method for the determination of trace element zinc in milk. Methods: In H2SO4 medium, trace amount of zinc catalyzed the reaction of xylenol orange with hydrogen peroxide, and the degree of discoloration ΔA of xylenol orange after oxidation was linear with the content of trace zinc. Based on this, A New Method of Determining Trace Zinc with Xylenol Orange by Fading Spectrophotometry. Results: The maximum absorption wavelength of this method was 690 nm. The apparent molar coefficient was 1.52 × 104 L / mol.cm. The linear range was 0-5.2 μg / ml. The minimum detectable limit was 0.13 μg / ml. The relative standard deviation was 1.2 % ~ 6.0%, the determination results and the standard method was no significant difference. Conclusion: The method is simple, linear range, accuracy, and can be used for the determination of the actual samples.