紫外可见分光光度法测保健食品中铁的含量

Determination of iron content in health food by UV spectrophotometry

目的建立一种分光光度法测定保健食品中铁的含量的分析方法。方法以硫酸溶液为反应媒介,利用三价铁离子催化过氧化氢氧化甲基橙褪色反应机制,采用分光光度法对样品进行测定。结果在最优条件下,在0~1.0μg/m L的区间范围内三价铁离子浓度(c)与ΔA(ΔA=非催化体系吸光度A0-催化体系吸光度A)之间存在着良好的线性关系,线性回归方程为ΔA=0.5263c+0.0035(r^2=0.9994)。利用该测定方法对琥珀酸亚铁片、多维铁复合物胶囊、多维铁口服溶液、钙铁锌口服液和朴雪口服液5种样品进行测定,含铁量依次为46 mg/0.1 g、132 mg/0.15 g、0.892 mg/m L、0.138 mg/m L、0.470 mg/m L。精密度实验结果显示标准偏差为0.0071,相对标准偏差为1.31%。该方法的检出限为2.13×10^(-8) g/m L,加标回收率均在97%~101%范围内,测定结果符合测定要求。结论该方法结果准确可靠、操作简便,可用于保健食品中铁的含量测定。

Objective To establish a method for determination of iron content in health food by speetrophotometry. Methods Sulfuric acid solution was used as the reaction medium, the reaction mechanism of the decolorization of methyl orange by hydrogen peroxide catalyzed was reference, and ferric ions was determined by spectrophotometry. Results Under the optimal conditions, ferric iron concentration （c） and △A （△A=non catalytic systems absorbanee A0-catalytic system absorbance A） had good linear relationships in the range of 0-1.0 μg/mL. The linear regression equation was △A=0.5263c＋0.0035, and the correlation coefficients was 0.9994. A total of 5 samples including ferrous succinate tablets, multidimensional ferric compound capsules, oral solution of multidimensional ferric iron, oral solution of calcium-ferric zinc and oral solution of piaoxue were measured by this method, and the iron content in the samples were 46 mg/0.1 g, 132 mg/0.15 g, 0.892 mg/mL, 0.138 mg/mL and 0.470 mg/mL, respectively. The precision test results showed that the standard deviation was 0.0071 and the relative standard deviation was 1.31%. The limit of detection was 2.13×10^-8 g/mL, the recovery rates were all within the range of 97%-101%, and the test results met the test requirements. Conclusion This method is accurate, reliable and easy to operate, which can be used for the determination of iron in health food.