尿碘的过硫酸铵消化-低砷量砷铈催化分光光度测定法的化学动力学研究与应用  

Chemical kinetics study and application of a method with low usage amount of arsenic trioxide for determining urinary iodine by arsenite-ceric catalytic spectrophotometry using ammonium persulfatedigestion

作　　者：张亚平[1] 黄嫣红[1] 李呐[1] 张淑琼[1] 

机构地区：[1]福建省厦门市疾病预防控制中心检验科,361021

出　　处：《中华地方病学杂志》2013年第3期318-324,共7页Chinese Journal of Endemiology

基　　金：卫生部卫生标准制修项目（20111801）

摘　　要：目的研究新修订的尿碘的过硫酸铵消化一低砷量砷铈催化分光光度测定方法的化学动力学特性。探讨砷铈反应温度与反应时间操作偏差对测定结果的影响。方法在不同的反应温度和反应时间测定碘标准系列的砷铈反应吸光度（A）值，结果按化学动力学有关方程式做化学动力学分析，计算比较新修订法和原标准法的A值变化半衰期及变化值。推导新修订法的化学动力学模型及含反应温度、反应时间和反应速率常数因子的尿碘测定结果相对误差计算式，计算反应温度和反应时间操作偏差所致的尿碘测定结果相对误差。结果新修订法的亚砷酸使用量减少至原标准法的四分之一，实验得其标准曲线，各浓度管不同反应时间（t）测得A值，各以lnA对t作图，结果为直线关系，线性相关系数（r）为-0．9995--0．9999，符合化学一级反应的动力学实验特征；20～35℃范围内实验得到的反应速率常数（K）与反应温度（r）的关系符合Arrhenius方程式；在各温度下实验得到的碘质量浓度（C）与A值，均有很好的C=a＋blnA线性关系，相关系数（r）绝对值〉0．9990。计算比较新修订法与原标准法在20、25、30、35℃反应温度下的A值变化半衰期，其中25℃下，新修订法、原标准法的0～300μg／L碘标准系列A值变化半衰期分别为191．0—11．4min、66．8—10．2min；在25℃反应40min的相同条件下，新修订法与原标准法碘O～300μg／L标准曲线的A值梯度相近（斜率分别为-133．7、-139．2），但原标准法标准曲线的A值与反应初始A。值间的差值是新修订方法的1．4—3．7倍。建立了该方法的化学动力学模型，得出了样品管反应温度偏离±1．0、±0．5、±0．3oC或反应时间偏离±lmin所引起的尿碘测定结果相对误差的系列数据，数据表明新修订法中反应温度和反应时间偏差引起的测定误差小于原Objective To study the chemical kinetics characteristics in a new revised method with low usage amount of arsenic trioxide for determining urinary iodine by arsenite-cerie catalytic speetrophotometry using ammonium persulfate digestion, and to study the impact of operating bias in arsenite-ceric reaction temperature and reaction time on final results in this method. Methods The absorbances （A） of arsenite-eeric reaction of iodine standard series were measured at different reaction temperature and time, and the results were analyzed according to the chemical kinetics equation. The change values and half-life of A values of the new revised method and the current standard method were calculated. The chemical kinetics model of reaction system for this new revised method was deduced from experimental results. The calculation formula of result relative error for urinary iodine determination was deduced based on constants reaction temperature and reaction time and reaction rate constantfactor. The result relative errors caused by operation deviation of reaction temperature or reaction time in the determination of urinary iodine were calculated. Results The usage amount of arsenious acid solution in the new revised method was only a quarter of usage amount of the current standard method （WS/T 107-2006）. A values of each concentration of standard curve series at different reaction time t were obtained, the lnA to t mapping was a straight line, the linear correlation coefficients were - 0.9995 - - 0.9999. These results were in accord with the characteristic of chemical first-order reaction. Relationships between the reaction rate constant K and the reaction temperature T in the temperature range of 20 - 35 ℃ were well accord with Arrhenius equation. The A values and iodine concentrations （C） at various experimental temperatures showed good C = a ＋ blnA linear relation, the absolute value of the linear correlation coefficient（｜ r ｜） 〉 0.9990. After calculation and comparison of changes in the half-

关 键 词：碘 尿 分光光度法 化学动力学 相对误差 

分 类 号：R446.1[医药卫生—诊断学]