Polarographic study of Europium(III)-L-proline complexes

Abstract

The electro-reduction of europium(111) at the dropping mercury electrode (d.m.e.) has been studied in various supporting electrolytesl-10 and in complexing media by several workers. Chelating agents, viz. EDTA, HEDTA, complexion 111, have been employed by some investigators.11-16 Formate and acetate complexes of europium(111) were studied by Nacero and coworkers.17Js Zutshilg reported results on europium(111) benzoate and salicylate complexes in formamide-water mixtures. Ide20 noted that Elp of the first reduction wave of europium( Holleck21 reported complexation of europium(111) with citrates, tartrates, salicylates, and lactates. However, complexation studies of rare earths with amino acids are sparse in the literature. Amino acids possess both nitrogen and oxygen sites available for coordination and stable complexes are expected which can be of analytical importance in separation of rare earths and indirect determination of amino acids. Preliminary studies made by the author22 on the europium-DL-tryptophan system revealed the formation of one complex [Eu(tryp)]2+ with the instability