碘(Ⅴ)-碘化物-溴化十六烷基三甲基铵体系共振光散射法测定磷矿中碘  

Resonance light scattering method for the determination of iodine in phosphorus ore with iodine(Ⅴ)-iodide-cetyltrimethylammonium bromide system

作　　者：李人宇[1] 李咏梅[2] 周家宏[3] 韦芳[1] 

机构地区：[1]连云港师范高等专科学校,江苏连云港222006 [2]淮海工学院化学工程系,江苏连云港222005 [3]南京师范大学分析测试中心,江苏南京210097

出　　处：《冶金分析》2009年第5期31-34,共4页Metallurgical Analysis

基　　金：国家自然科学基金项目(20603018);连云港市科技项目(SH0816,CN0646)资助

摘　　要：基于在0．015mol／L磷酸中，碘（V）与过量的I^-反应生成I3-，I3^-进一步与溴化十六烷基三甲基铵（CTMAB）反应成1：1离子缔合物，导致共振光散射（RLS）明显增强，建立了共振光散射法测定痕量碘的新方法。试验了酸度、试剂用量、温度和时间的影响，确定了最佳测定条件。最大共振光散射峰位于469nm，共振光散射增强量与碘（V）含量在0．02～0．83μg／mL范围内线性关系良好，方法的检出限为0．425μg／L。大量的共存离子不影响测定，Fe^3＋，Pb^2＋，Cu^2＋的干扰用EDTA消除。方法用于测定磷矿中碘，结果与碘篮分光光度法一致，相对标准偏差小于0．37％（n=5），加标回收率为99．2％～101．0％。A new resonance light scattering （RLS） method for the determination of trace iodine was developed. The method is based on the fact that I（V） reacts with excess I^- in 0. 015 mol/L H3PO4 to produce I3^-, and I3^- further reacts with cetyltrimethylammonium bromide （CTMAB） to form an ionassociation complex （1 ： 1）, which results in great enhancement of RLS. The optimal conditions for determining I（V）, including acidity, reagents dosage, temperature and time, were studied. A good linear dependence of RLS intensity occurred on I（V） mass concentration in the range of 0.02- 0.83 μg/mL at the maximum RLS peak （469 nm）. The detection limit was 0. 425 μg/L. A great deal of coexisting ions had no intereference with the determination. The interferences from Fe^3＋, Pb^2＋ and Cu^2＋ were masked by EDTA. This method was applied to determine iodine in phosphorus ore samples. ＇The results were in good agreement with those obtained by iodine-blue spectrophotomerty. The RSD was below 0.37 % （n=5）, and recoveries after I（V） standard solution addition varied from 99. 2 % to 101.0 %.

关 键 词：碘 共振光散射 碘化物 溴化十六烷基三甲基铵 磷矿 

分 类 号：P575[天文地球—矿物学]