碘(V)-碘化物-番红花红T体系双波长分光光度法测定食盐中碘  

Double-wavelength spectrophotometric determination of iodine in saltwith I(V)-iodide-safranine T system

作　　者：李人宇[1,2] 李咏梅[2] 韦芳[1] 黄勇波[1] 

机构地区：[1]连云港师范高等专科学校,江苏连云港222006 [2]淮海工学院江苏省海洋资源开发研究院,江苏连云港222005

出　　处：《中国调味品》2010年第2期88-91,96,共5页China Condiment

基　　金：连云港市科技项目(SH0816);江苏省海洋资源开发研究院科技开放基金资助项目(JSIMR09C08)

摘　　要：在0．2mol／L磷酸中，碘（V）与过量的I-反应生成I3-，I3-进一步与番红花红T（ST）形成稳定的2：1离子缔合物，360nm处出现正吸收峰，513nm处出现负吸收峰。选定测量波长为360nm，参比波长为513nm，建立了双波长分光光度法测定碘的新方法。碘（V）浓度在0～0．7μg／mL范围内服从比尔定律，表观摩尔吸光系数为1．27×10^5L·mol^-1·cm^-1，检出限为11．9μg／L。方法用于测定低钠盐和锌强化营养盐中碘，结果与碘量法一致，相对标准偏差小于1．54％（n=5），回收率为98．4％～99．1％。A new method for determination of iodine was developed by double-wavelength speetrophotometry u- sing 360 nm as the measurement wavelength and 513 nm as the reference wavelength. The method is based on the reaction of I（V） with excess I in 0.2 mol/L H3PO4 to produce I3 ,and it further reacts with safranine T （ST） to form a stable ion-association complex（2 ： 1）, which exhibiting a positive ab- sorption peak at 360 nm and a negative absorption peak at 513 nm. Beer＇s law was obeyed for 0 0. 7 μg/mL I（V）. The apparent molar absorptivity was 1.27 × 10^5 L · mol^-1 · cm^-1 , and the limit of detection was 11.9μg/L. The method was applied to determine iodine in low sodium salt and salt for- tified with zinc. The results showed good agreement with those obtained by iodimetry. RSD was less than 1.54 %（n = 5）. Recovery varied from 98.4 % to 99.1%.

关 键 词：双波长分光光度法 碘 碘化物 番红花红T 离子缔合物 

分 类 号：TS365[轻工技术与工程]