par Abo El-Maali, Nagwa ;Patriarche, Gaston
Référence Analytical letters, 22, 5, page (1251-1270)
Publication Publié, 1989
Article révisé par les pairs
Résumé : The equilibria existing in unbuffered aqueous medium between lead ions and folic acid or its related derivatives (pterin, pterin-6-carboxylic acid, pteroic acid and glutamic acid) have been investigated using differential pulse polarography. All these compounds, except pterin-6-carboxylic acid and glutamic acid, exhibit three consecutive complexes with increasing ligand concentration. Their stoichiometry (1:1, 1:2 and 1:3 metal-to-ligand respectively) and their stability constants are quite similar, indicating that the pterin moiety is the active site for complexation and that the side chain is not involved in this reaction. Glutamic acid has no complexing properties towards lead ions. Pterin-6-carboxylic acid however exhibits only one strong complex, attributed to the carboxylic group fixed at the 6-position on the pterin structure. The influence of several experimental parameters is also considered. © 1989, Taylor and Francis Group, LLC. All rights reserved.