LAUSR

Abstract Fluorescence quenching, very often, has been employed as a suitable technique for characterization of the immediate environment of a fluorophore. This paper reports the absorption and fluorescence characteristics of an antimalarial drug, chloroquine, in presence of the salt copper chloride (CuCl2) in aqueous and micellar systems. Chloroquine fluorescence was quenched considerably by the copper ion (Cu2+); quenching ability of Cu2+ in micellar solution of the cationic surfactant cetyltrimethylammonium chloride (CTAC) is higher than that in water while for the nonionic surfactant polyoxyethylene (20) cetyl ether (Brij 58) it has much lower quenching efficiency. Downward deviations in Stern-Volmer (SV) plots were observed for all the systems. Possibly, the chloroquine molecules are inserted somewhat deeper inside the micelles of Brij 58 as compared to the CTAC micelles and in Brij 58 micelles the fluorophore might be less exposed to the aqueous phase to become available for the metal ion quenching.