结晶紫-亚砷酸钠体系光度法测定食盐中的碘  

DETERMINATION OF TRACE IODINE IN SALT BASED ON CRYSTAL VIOLET-SODIUM ARSENITE SPECTROPHOTOMETRIC SYSTEM

作　　者：卞永东 王丹丹[2] 范大和[2] 吴升德[2] 吴炜[2] 

机构地区：[1]盐城市产品质量监督检验所,江苏盐城224005 [2]江苏盐城工学院现代分析中心,江苏盐城224001

出　　处：《食品研究与开发》2008年第5期102-105,共4页Food Research and Development

摘　　要：在盐酸介质中,过量的亚砷酸钠还原碘酸根离子释放出I3-,其与结晶紫发生氧化还原反应,且反应前后吸光度的差值与碘酸根的浓度成正比,建立了紫外分光光度法测定微量碘的新方法。碘酸钾含量在6mg/L～20mg/L范围内服从朗伯-比耳定律,线性方程为Y=0.0457+0.4847X,相关系数r=0.9958,检出限为0.0686mg/L(以KIO3计)。用该方法测定了食盐的碘含量,回收率在96.0%～101.0%之间。A new spectrophotometric method for the determination of trace amount of iodine was proposed. The sodium arsenite reacts with potassium iodide in acidic solution, giving rise to I3^- that can oxidize crystal violet selectively. The absorbance at 463 nm increased proportionally to the amount of potassium iodide. A good linearity was observed over the potassium iodide concentration range 6 mg/L -20 mg/L with a linear coefficient of 0.995 8. The detection limit of the method is 0.068 6 mg/L. The method was used for the determination of trace amount of iodine in salt with the recovery from 96.0 % to 101.0 %.

关 键 词：结晶紫 碘 分光光度法 

分 类 号：TS37[轻工技术与工程] O657.3[理学—分析化学]