Zn^(2+)-硫氰酸铵-瑞士色素体系褪色光度法测定食盐中锌  

Fading spectrophotometric determination of zinc in salt with Zn^(2+)-ammonium thiocyanate-Wright's stain system

作　　者：李人宇[1,2] 李咏梅[2,3] 卢洋[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 [3]淮海工学院化学工程学院,江苏连云港222005

出　　处：《中国调味品》2010年第5期89-92,共4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项目(JSIMR09C08)

摘　　要：吐温20存在下,在pH5.7 NaAc-HAc缓冲溶液中,Zn2+与硫氰酸铵和瑞士色素发生离子缔合反应,使瑞士色素褪色,据此建立了褪色光度法测定痕量锌的新方法。最大褪色波长为656 nm,体系的褪色程度与Zn2+浓度在0～0.24μg/mL范围内呈线性关系,表观摩尔吸光系数1.58×105L.mol-1.cm-1,检出限为2.56μg/L。方法用于测定锌强化营养盐和健康平衡盐中锌,相对标准偏差为0.64%～0.87%(n=5),回收率为99.0%～99.7%。A new fading spectrophotometric method for determination of trace zinc was developed.It was based on the ion-association reaction of Zn^2＋ with ammonium thiocyanate and Wright＇s stain in NaAc-HAc buffer solution at pH 5.7 in presence of Tween 20,leading to fading of Wright＇s stain.The maximum fading wavelength locates at 656 nm.The system＇s fading degree was linear with the concentration of Zn^2＋in the range of 0～0.24 μg/mL.The apparent molar absorption coefficient was 1.58×10^5L.mol^-1.cm^-1d the detection limit was 2.56 μg/L.The method has been applied to the determination of zinc in zinc-fortified nutritious salt with and health balance salt.RSDs of 5 determinations for Zn^2＋were found to be 0.64%～0.87%.Recoveries of Zn^2＋ were found to be 99.0%～99.7%.

关 键 词：褪色光度法 锌 硫氰酸铵 瑞士色素 吐温20 

分 类 号：TS365[轻工技术与工程]