Zn^(2+)-邻菲啰啉-刚果红体系双波长光度法测定食盐中锌含量  

Dual-wavelength Spectrophotometric Determination of Zinc Content in Salt with Zn^(2+)-phen-Congo Red System

作　　者：李人宇[1] 李咏梅[2] 陶明涛[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学院,江苏连云港222005

出　　处：《中国调味品》2012年第11期84-88,共5页China Condiment

摘　　要：增敏剂β-环糊精存在下,Zn2+与邻菲啰啉(phen)和刚果红(CR)在pH 7.0NH4Ac缓冲溶液中反应生成稳定的离子缔合物[Zn(phen)3]CR,使刚果红褪色,574nm处出现正吸收峰,502nm处出现负吸收峰。选定测量波长为574nm,参比波长为502nm,据此建立了双波长光度法测定微量锌的新方法。表观摩尔吸光系数为9.8×104 L/mol/cm,线性范围为0～0.32μg/mL,检出限为5.7μg/L。方法用于测定锌强化营养盐和健康平衡盐中锌含量,相对标准偏差为0.70%～0.83%(n=5),回收率为99.37%～100.04%。In the presence of β-cyclodextrin used as sensitizer, Zn^2＋ reacted with phen and congo red （CR） to form a stable ion-association complex [Zn（phen）3]CR in NH4Ae buffer solution at pH 7.0, which led to the fading of congo red. As a result, there was a positive absorption peak at 574 nm and a negative absorption peak at 502 nm. A new method for determination of micro zinc by double-wave- length spectrophotometry using 574 nm as the detection wavelength and 502 nm as the reference wave- length was developed. The apparent molar absorption coefficient was 9.8 ×10^4 L/mol/cm. The linear range of the determination was 0-0.32μg/mL, and the limit of detection for zinc was 5.7 μg/L. The method has been applied to the determination of zinc in zinc-fortified nutritious salt and health halance salt. RSDs of 5 determinations was 0.70%-0.83%. Recoveries were 99.37%-100.04%.

关 键 词：双波长分光光度法 锌 邻菲啰啉 刚果红 Β-环糊精 

分 类 号：TS364[轻工技术与工程]