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目的建立简便快速消解奶粉样品,实现其总碘含量测定的方法。方法用高氯酸、氯酸钾混合湿法消解样品溶液2小时,用砷铈催化分光光度法测定其碘含量。由吸光度值与碘浓度的对应关系,计算出样品中碘的含量。结果检测范围0~100μg/L,标准曲线相关系数为-0.999 6~-0.999 9;精密度:测定奶溶液样品中碘含量为20.11μg/L、60.45μg/L和86.55μg/L时,变异系数(CV)分别为2.54%、1.85%和1.58%;准确度:对低、中、高3种不同浓度碘含量的奶粉溶液加标回收率分别为98.90%、101.02%和99.66%(n=6),平均回收率为99.86%。结论本方法适合应用于奶粉中总碘的含量测定。
Objective To establish a simple and rapid digestion of milk powder samples to achieve its total iodine content determination method. Methods The sample solution was digested with perchloric acid and potassium chlorate by wet method for 2 hours. The content of iodine was determined by arsenic and cerium catalytic spectrophotometry. By the absorbance value and the corresponding relationship between iodine concentration, calculate the content of iodine in the sample. The results showed that the detection range was 0 ~ 100μg / L and the correlation coefficient of standard curve was -0.999 6 ~ -0.999 9; The precision: when the content of iodine in milk solution was 20.11μg / L, 60.45μg / L and 86.55μg / L, (CV) were 2.54%, 1.85% and 1.58%, respectively. Accuracy: The recoveries of milk powder solutions with three different concentrations of iodine were 98.90%, 101.02% and 99.66% respectively (n = 6), the average recovery was 99.86%. Conclusion This method is suitable for determination of total iodine in milk powder.