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A comparison of the determination of stability constants of complexes of Pb(II) with amino acids using micro‐pH‐metric titrations and cyclic voltammetry
Author(s) -
Lu AiRu,
Pettit D. Leslie,
Bernard Gareth,
Gregor E. Jan
Publication year - 1991
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.19910090603
Subject(s) - chemistry , titration , cyclic voltammetry , metric (unit) , stability constants of complexes , analytical chemistry (journal) , voltammetry , conductometry , convolution (computer science) , inorganic chemistry , electrochemistry , chromatography , electrode , aqueous solution , operations management , machine learning , artificial neural network , computer science , economics
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°C and I = 0.10 mol·dm −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′ considerably 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 coprocessors. 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 more reliable when determined by pH‐metric titration.