摘要
在0．048mol／L H3PO4中，碘（V）与过量的I^-反应生成I3^-，加入NaAc后，I3^-再与吖啶橙（AO）生成1：1的离子缔合物．使AO发生褪色反应，据此建立了褪色光度法测定碘的新方法。可见光区最大褪色波长为491nm．碘（V）质量浓度在0-0．48μg／mL范围内服从比尔定律，表观摩尔吸光系数ε为1．72×10^5L／mol·cm，检出限为7．47μg／L。MnO4^-等氧化性离子的干扰可加入盐酸羟胺消除．Ca^2＋和Fe^2＋等金属离子的干扰经阳离子交换树脂预分离去除。方法用于测定磷矿中碘，结果与国标法一致，相对标准偏差小于1．32％（n=5）．加标回收率为100．3％～101．0％。
A new fading spectrophotometric method for determination of trace iodine was developed. I（V） reacts with excess I - in 0. 048 mol/L H3PO4 to produce I3^-. After adding NaAc, I3^-, further reacts with acridine orange （AO） to form an ionassociation complex （ 1 ： 1 ）, leading to the fading of AO. Beer＇ s law for 0 - 0.48/μg/mL I（V） with the maximum fading wavelength locating at 491 nm in the visible region. The apparent molar absorption coefficient （ε） was 1.72 ×10^5 L·mol^-1 ·cm^-1 and the detection limit was 7.47 μg/L. The interferences of oxidants including MnO4^- were eliminated by adding hydrazine hydrochloride. The interferences of metal ions such as, Ca^2＋ and Fe^2＋ were separated by cation exchange resin. The method was applied to determine iodine in phosphate ore samples. The results well agreed with those obtained using national standard method. RSDs of 5 determinations for iodine were less than 1.32 %, and recoveries after I（V） standard solution addition varied from 100.3 % to 101.0 %.
出处
《化工矿物与加工》
CAS
北大核心
2009年第6期15-18,共4页
Industrial Minerals & Processing
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
关键词
褪色光度法
碘
碘化物
吖啶橙
离子缔合物
fading spectrophotometry
iodine
iodide
acridine orange （AO）
ion-association complex
