Novel 4-amino-2-methyl-8-(trifluoromethyl)quinoline-based magnetic nanostructures for highly sensitive detection of zinc ions in aqueous solutions

Abstract

© 2018 Elsevier Ltd. Novel 4-amino-2-methyl-8-(trifluoromethyl)quinoline based magnetic nanosensors, Fe3O4@SiO2-PEG-4AQ and Fe3O4@SiO2-4AQ, were successfully fabricated and characterised. Enhanced fluorescent intensity was demonstrated by both nanosensors. Upon complexation with zinc ions, a further enhancement of 13.5-fold was revealed by Fe3O4@SiO2-PEG-4AQ. A red shift of 42 nm was also observed. The presence of other metal cations including Ni2+, Co2+, Ca2+, Cd2+, Hg2+, Mg2+, Mn2+and Ag+, showed no interference towards Zn2+. A sensitive detection limit of 0.0065 µM and 0.0125 µM was indicated by Fe3O4@SiO2-PEG-4AQ and Fe3O4@SiO2-4AQ respectively. The high sensitivity and selectivity remained constant within a wide range of pH values and were reversible upon treatment with EDTA. The PEG spacer between the magnetic core and the fluorophore offered further improvement of fluorescence intensity and detection sensitivity. To the best of our knowledge, this is the first study on 4-aminoquinoline based reusable nanochemosensor for zinc ion detection.