摘要
目的验证食物中碘的碱灰化-砷铈催化分光光度测定方法的精密度、灵敏度和准确度。方法在样品中加入碳酸钾、硫酸锌、氯酸钾、氯化钠混合碱性助剂，于105℃下干燥3h，电炉炭化约0．5h，置于马弗炉中600℃灰化4h．用水溶解灰粉后取上清液，砷铈催化分光光度法测定含碘量，并进行标准曲线线性范围及线性关系、灵敏度实验；选择3种含碘量不同的南瓜采用碱灰化后，分别做精密度和加标回收率实验；同时测定美国标准物（碘）和尿碘国家标准物，比较测定偏差。结果采用碱灰化-砷铈催化分光光度测定，碘检测范围为4．4～250．0ng；标准曲线的相关系数为-0．9997～-0．9993；当样品含碘量为45．8、145．0、195．6μs／ks时，变异系数（CV）分别为4．3％、3．0％、3．9％；低[（47．2±2．6）μg／kg]、中[（71．9±3．3）μg／kg]、高[（95．9±2．4）μg／kg]3种不同含碘量样品加标回收率分别为96．8％、97．8％、97．6％；对美国标准物测定，相对偏差为-6．5％；对国家尿碘（低、中、高）标准物测定，相对偏差分别为11．0％、10．7％和10．7％。结论食物中碘的碱灰化-砷铈催化分光光度测定方法适宜于食品中总碘的测定 ,也适宜于尿中总碘的测定。
Objective To verify the determination of iodine in foodstuff by dry ashing As^3＋-Ce^4＋ catalytic spectrophotometry. Methods The mixture of foodstuff powder and the solution of K2CO3, ZnSO4, KClO3 and NaCI was heated and dried at 105 ℃ for 3 hours, then heated by a adjustable electric heater for around 0.5 hour, transferred into muffle furnace to cremated at 600 ℃ for 4 hours. The dissolved ash was measured by As^3＋-Ce^4＋ catalytic spectrophotometry. The linear range of the calibration and sensitivity were tested; The precision and accuracy for three kinds of iodine in samples of different pumpkins were tested; The iodine contents of standard urine samples and the American standard materials were tested as well. Results This testing covers iodine ranged from 4.4 ng to 250 ng. The relevance coefficient of standard curve was from - 0.9997 to - 0.9993. The pumpkin iodine contents detected were 45.8,145.0,195.6 μg/kg, with constant variables of 4.3%, 3.0% and 3.9% respectively. The recovery was 96.8%, 97.8% and 97.6% for three kinds of iodine in samples[ （47.2 ± 2.6）, （71.9 ±3.3）, （95.9 ± 2.4）μg/kg]. The relative error was - 6.5% when the American standard materials were assessed. The relative error were 11.0%, 10.7% and 10.7% when the standard urine samples of three kinds were tested. Conclusion This method, easy to be performed with better precision and accuracy, is suitable to measure food iodine as well as total iodine in urine.
出处
《中国地方病学杂志》
CAS
CSCD
北大核心
2008年第3期314-316,共3页
Chinese Jouranl of Endemiology
基金
卫生部科学研究基金（WKj2003-2-003）
志谢 中国疾病预防控制中心传染病预防控制所碘缺乏病参照实验室刘列钧老师和李素梅老师对分析实验提供指导和帮助,谨致谢意
关键词
食品
尿
碘
碱灰化
分光光度法
Food
Urine
Iodine
Ashing
Catalytic spectrophotometry
