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

In this work, a luminescent lanthanide complex, namely, Eu(tta)3phen (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-SiO2@Eu(tta)3phen) are composed of chitosan and polyethylene oxide containing silica nanoparticles, encapsulating the Eu(tta)3phen. The nanofibers are stabilized by treatment with sodium bicarbonate (NaHCO3) aqueous solution as neutralizer and then repeatedly washed with deionized water. A more stable Na-CS/PEO-SiO2@Eu(tta)3phen fiber film is obtained as a fluorescence sensor for Cu2+ ions. The Na-CS/PEO-SiO2@Eu(tta)3phen 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-SiO2@Eu(tta)3phen 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.