Gum acacia-based silver nanoparticles as a highly selective and sensitive dual nanosensor for Hg(ii) and fluorescence turn-off sensor for S2? and malachite green detection

摘要

A facile and green method was adopted to synthesize highly selective gum acacia-mediated silver nanoparticles as dual sensor (fluorescence turn-on and colorimetric) for Hg( II ) and fluorescence turn-off sensor for S ~(2?) and malachite green. The mechanism proposed for a dual response towards Hg( II ) is the redox reaction between Ag(0) and Hg( II ), resulting in the formation of Ag( I ) and Hg(0) and electron transfer from gum acacia to Ag( I ), which further leads to the formation of an Ag@Hg nanoalloy. The enhanced fluorescence signal was quenched selectively by S ~(2?) owing to the formation of Ag _(2) S and HgS. The reported nanosensor was found to be useful for sensing malachite green via the inner filter effect. The linear ranges were 3 nmol L ~(?1) to 13 μmol L ~(?1) for Hg( II ), 3–170 μmol L ~(?1) for S ~(2?) and 7–80 μmol L ~(?1) for malachite green, and the corresponding detection limits were 2.1 nmol L ~(?1) for Hg( II ), 1.3 μmol L ~(?1) for S ~(2?) and 1.6 μmol L ~(?1) for malachite green.