A comparison of the determination of stability constants of complexes of Pb(II) with amino acids using micro-pH-metric titrations and cyclic voltammetry

作     者：LU Ai-Ru PETTIT Leslie D.BERNARD Gareth GREGOR Jan E. 

作者机构：Department of ChemistryNorthwest Normal UniversityLanzhou 730070 School of ChemistryThe University of LeedsLeedsLS29JTUK 

出 版 物：《Chinese Journal of Chemistry》 (中国化学(英文版))

年 卷 期：1991年第9卷第6期

页      面：493-498页

核心收录：

学科分类：07[理学] 0703[理学-化学] 

主　　题：A comparison of the determination of stability constants of complexes of Pb with amino acids using micro-pH-metric titrations and cyclic voltammetry pH II 

摘      要：This paper reports the determination of stability constants for complexes of Pb(Ⅱ) with Gly, Ala, Asp and Gly-Gly using both micro-pH-metric titrations and the application of convolution-de- convolution cyclic voltammetry at 25℃ and I = 0.10 ***^(-3)(KNO_3). Stability constants were calculated from pH-metric data using the SUPERQUAD computer program and cyclic voltammograms were collected, stored and manipulated using the E G and G CONDECON 300 software. A consider- ably larger ligand: metal ratio (e.g. 50:1) was possible using voltammetry. Under these conditions, hydroxy complex formation was minimised and the formation of bis-complexes optimised. Computer based calculations were carried out on PC-compatible microcomputers fitted with mathematics co- processors. Evaluation of results from the two techniques suggests that stability constants for the species [PbL_2] are reliable when calculated from voltammetry while those for [PbL] are mote reliable when determined by pH-metric titration.