Stable chitosan fluorescent nanofiber sensor containing Eu3+ complexes for detection of copper ion.

In this work, a luminescent lanthanide complex, namely, Eu(tta) 3 phen (Eu = europium, tta = 2-thenoyltrifluoroacetone, phen = 1, 10-phenanthroline) is used as a luminescent dopant to prepare fluorescent nanofiber films. The resulting nanofibers (CS/PEO-SiO 2 @Eu(tta) 3 phen) are composed of chitosan and polyethylene oxide containing silica nanoparticles, encapsulating the Eu(tta) 3 phen. The nanofibers are stabilized by treatment with sodium bicarbonate (NaHCO 3) aqueous solution as neutralizer and then repeatedly washed with deionized water. A more stable Na-CS/PEO-SiO 2 @Eu(tta) 3 phen fiber film is obtained as a fluorescence sensor for Cu2+ ions. The Na-CS/PEO-SiO 2 @Eu(tta) 3 phen has high sensitivity, and a wide detection range. The response is linear in the concentration range from 10 to 90 μmol/L, and the detection limit is 0.826 μmol/L. In addition, Na-CS/PEO-SiO 2 @Eu(tta) 3 phen nanofiber film can be used as a recyclable sensor for the detection of Cu2+ ions in aqueous solution due to its good recyclability, selectivity and rapid optical response. • CS/PEO-SiO 2 @Eu(tta) 3 phen film is stabilized by neutralization with weak base. • Na-CS/PEO-SiO 2 @Eu(tta) 3 phen film can be quenched after Cu2+ solution is dropped on it. • Na-CS/PEO-SiO 2 @Eu(tta) 3 phen film is capable of accurately detecting 10–90 μmol/L of Cu2+, LOD is 0.826 μmol/L. • Na-CS/PEO-SiO 2 @Eu(tta) 3 phen film can still be used as a Cu2+ sensor after 5 cycles of use. [ABSTRACT FROM AUTHOR]