Greenish-Yellow Emitting Carbon Dots as 'On-Off-On' Fluorescent Probe for Selective Determination of Mercury (II) and Sulphide Ions

摘要

Herein, we have reported a simple ratiometric yellow fluorescent probe based on carbon dots for selective determination of Hg2+ and S2- through a fluorescence 'ON-OFF-ON' strategy. The yellow emitting nitrogen doped carbon dots (Y-NCD's) were synthesized by prolonged thermal carbonisation of p-hydroxy benzoic acid and citric acid dissolved in ammonia solution at 180 degrees C. The purified Y-NCD's shows excitation dependent emission with maximum intensity at 550 nm showing bright yellow fluorescence when excited at 480 nm. The linear response for detection of Hg2+ ions ranges from 0 to 260 nM with a detection limit of 27.2 nM whereas the linear range for sulphide ions is from 0 to 1.1 mu M with limit of detection 0.11 mu M. The proposed sensor show excellent applicability for real sample analysis with satisfactory results.