碘化物-甲基紫体系共振瑞利散射法测定痕量铅  

Resonance Rayleigh Scattering Method for the Determination of Trace Amounts of Lead with the Iodide -Methyl Violet System

作　　者：王丹[1] 罗红群[1] 李念兵[1] 刘绍璞[1] 

机构地区：[1]西南师范大学化学化工学院,重庆400715

出　　处：《西南师范大学学报（自然科学版）》2004年第6期1005-1008,共4页Journal of Southwest China Normal University(Natural Science Edition)

基　　金：国家自然科学基金资助项目(29875019);重庆市科委资助项目(2002-7472).

摘　　要：在稀磷酸介质中,铅(Ⅱ)与过量的I-形成[PbI4]2-配阴离子并进一步与甲基紫形成离子缔合配合物时,会 明显增强共振瑞利散射(RRS)强度,最大RRS波长位于327nm.研究了该体系的共振瑞利散射光谱特性、主要影 响因素和反应的最佳条件,在2.0×10-3～3.0×10-2μg/mL范围内,共振瑞利散射强度与铅的浓度成线性关系, 实验结果表明该方法有很高的灵敏度,铅(Ⅱ)的检出限为0.6ng/mL,可用于对自来水中痕量铅的直接测定.In dilute phosphoric acid solution, lead(Ⅱ) reacts with excess of I^- to form [PbI_4]^(2-) anionic complex, which reacts further with methyl violet(MV) to form an ion-association complex. This results in a significant enhancement of resonance Rayleigh scattering(RRS) intensity and the maximum RRS peak is at 327 nm. The characteristics of RRS spectrum of the ion-association complex, the influencing factors and the optimum conditions of the reaction have been investigated. The intensity of RRS is directly proportional to the concentration of lead(Ⅱ) from 2.0×10^(-3)3.0×10^(-2) μg/mL. The method exhibits high sensitivities and the detection limit is 0.6 ng/mL. The method can be applied to the direct determination of trace amounts of lead in tap water samples.

关 键 词：甲基紫 共振瑞利散射 铅(Ⅱ) 强共振 碘化物 配合物 离子缔合 痕量铅 过量 反应 

分 类 号：O657[理学—分析化学] O647.2[理学—化学]