300～1200μg/L高质量浓度尿碘的砷铈催化分光光度测定方法

300～1200 μg/L iodine in urine measured by As^(3+)-Ce^(4+) catalytic spectrophotometry using ammonium persulfate digestion

目的建立一个高质量浓度尿碘的测定方法,用于尿碘高于300μg/L样品的直接测定,便于高碘地区人群尿碘的监测工作。方法0.2ml尿样加1ml1mol/L过硫酸铵溶液于100℃下消化1h,冷却后加入2.5ml0.11mol/L亚砷酸溶液于30℃温浴15min,每管间隔一定时间(15￣30s)加入0.5ml0.053mol/L硫酸铈铵溶液准确反应18min后于405nm下1cm光程测定光密度值,根据光密度值的对数与含碘量成线性关系计算尿碘。结果检测范围为300￣1200μg/L;标准曲线的平均相关系数为0.9995;精密度:测定尿样含碘量为322.9、650.9、1149.4μg/L时,其变异系数(CV)分别为1.9%、1.9%、1.3%(n=6);准确度:对低、中、高3种不同含碘量的尿样加碘标回收率分别为97.9%、96.0%、99.7%(n=6),平均回收率为97.9%。结论本方法操作简易,结果准确,特别适宜于高碘地区的尿碘测定。

Objective To set up a new method for determining urinary iodine in a range of 300 - 1 200 μg/L by As^3＋-Ce^4＋ catalytic spectrophotometry using ammonium persulfate digestion to facilitate surveillance of urine iodine in areas of high concentration of iodine. Methods 0.2 ml of each urine sample was pipetted and was added with 1 ml 1.0 mol/L ammonium persulfate. All tubes were heated for 60 minutes at 100 ℃ and then cooled down to room temperature. 2.5 ml 0.11 mol/L arsenious acid solution was added into each tube. All the tubes were again warmed up for 15 minutes at 30℃. Finally, 0.5 ml of eerie ammonium sulfate solution at a concentration of 0.053 mol/L was added to each tube at 15 - 30 second intervals. 18 min after the first addition of eerie ammonium sulfate, its absorbance at 405 nm was read, Successive readings were read at the same interval, Results The calibration was in a range of 300 -1200μg/L. The variations （CV） were 1.9%, 1.9% and 1.3% when testing urinary iodine at 322.9 μg/L, 650.9 μg/L and 1149.4μg/L respectively, The average recovery was 97.9% in a range of 96.0- 99.7% when quantitatively measuring iodine added in different urine samples. Conclusion This method is suitable to measure high iodine in urine and easier to be performed with better precision and accuracy.