Selective uptake of copper (II) ions in water by chelating agent-impregnated liposomes

• Published in: BUNSEKI KAGAKU Vol. 51; no. 9; pp. 745 - 749
• Main Authors: HIGUCHI, Kazuyoshi, SAITOH, Tohru, HIRAIDE, Masataka
• Format: Journal Article
• Language: Japanese; English
• Published: Tokyo The Japan Society for Analytical Chemistry 01.09.2002; Japan Science and Technology Agency
• Subjects: 8-hydroxyquinoline; copper (II); humic acid; liposome; selective uptake
• ISSN: 0525-1931
• DOI: 10.2116/bunsekikagaku.51.745

Unilamellar vesicles (i.e., liposomes) having 0.4 μm diameters were prepared by an extrusion technique. The liposomes were composed of phosphatidylcholine, phosphatidylglycerol, cholesterol, and chelating agents. When liposomes containing 8-hydroxyquinoline (HQ) were added to a water sample, copper (II) ions were collected with a recovery of 76±3%. The recovery, however, was decreased to 44 or 30% when the sample contained 1 or 5 μg/ml of humic acid, respectively. This was probably due to the exclusion of the copper-humin complex from the surface of liposome. A selective uptake of free copper (II) ion was not achieved by other chelating agents (e.g., 1,10-phenanthroline and N-benzoyl-N-phenylhydroxylamine). The inclusion of (N-ditiocarboxy) sarcosine in the inner water pool of the liposome significantly enhanced the copper uptake, while maintaining the selectivity.