Design of magnetic-fluorescent based nanosensor for highly sensitive determination and removal of HG2+

A novel carboxymethyl chitosan-functionalized magnetic-fluorescent nanocomposites were synthesized and applied for simultaneous determination and removal of Hg 2+ . The resulting composites possessed strong paramagnetic effect and photoluminescence (PL) property measured at room temperature in the size range from 150 to 175 nm. The fluorescence of the resulting nanosensor could be effectively quenched by Hg 2+ ions. Under optimal conditions, the quenched fluorescence effect of Hg 2+ on the fluorescence of nanosensor found to be concentration dependent in the concentration range of 3 × 10 −7 –5 × 10 −6 mol/L. The detection limit of Hg 2+ was 9.1 × 10 −8 mol/L (n = 11). The influence of other coexisting ions on the fluorescence intensity of MFNPs nanosensor was also researched and coexisting ions displayed low interference effect response in detecting of Hg 2+ ions. The quenching mechanism was also considered and the result was proved as a static quenching process. In addition to the significant selectivity and sensitivity performance of nanocomposites sensor, it also has a excellent magnetic separation feature which would effectively avoid the secondary pollution.