摘要
目的研究新近修订的尿碘测定标准方法——过硫酸铵消化-砷铈催化分光光度测定方法中碘—的质量浓度(C)与测定吸光值(A)定量关系式C=a+blnA的实验条件范围;探讨砷铈反应温度与反应时间的适宜组合及其波动偏差对结果的影响。方法进行反应温度和时间对砷铈反应速率及测定吸光度影响的化学动力学实验分析。结果建立了测定该方法的化学动力学模型,测定反应为化学一级反应。证实砷铈反应在20～35℃范围内选择任一稳定的温度及固定的反应时间都有C=a+blnA定量关系,得出了反应温度与反应时间适宜配对组合系列数据(25℃、40min,27℃、36min,30℃、30min等),证实了该方法中反应温度和反应时间偏差引起的测定误差明显小于原氯酸消化法。结论采用过硫酸铵消化测定尿碘,使砷铈反应速率比修订前的氯酸消化法变慢,即减小测定误差,提高测定的精密度和准确度,又便于掌握和操作,易于普及和应用。
Objective To study the experimental condition range for calibrating relation C = a + blnA (C:iodine concentration, A:measured absorbance) in the modified method of ammonium persulfate digestion in determining urinary iodine and to seek a suitable combination of As3+ - Ce4+ reacting temperature and time for this method and the influence of its deviation on the final results. Methods Experimental chemical kinetics study was conducted to determine the influence of reacting temperature and time on As3+ - Ce4+ reacting rate and to measure the absorbance. Results A chemical kinetics model of reacting system for this method was established, in which first order reaction occurred. The calibration relation of C = a + blnA existed when As3+ - Ce4+ catalytic spectrophotometry was kept at a certain stable temperature range of 20 ～ 35 ℃ and in certain stable reacting time. The table of suitable combination of As3+ - Ce4+ reacting temperature and time for this method was obtained (such as 25 ℃,40 min; 27 ℃,36 min; 30 ℃,30 min,etc). The measured deviation caused by variance of As3+ - Ce4+ reacting temperature and time in this method was significantly less than the national standard method of chloric acid digestion (WS/T 107-1999). Conclusions The As3+ - Ce4+ reaction rate with the modified method of ammonium persulfate digestion is much slower than that of the method of chloric acid digestion. As a result, more precise, more accurate and easier to manipulate, this modified method tends to popularized for measuring iodine in urine.
出处
《中国地方病学杂志》
CAS
CSCD
北大核心
2005年第2期223-226,共4页
Chinese Jouranl of Endemiology
基金
卫生部卫生监督中心卫生标准资助项目(2003-2004)
