Preparation of g-CNQDs@Hg2+"on-off-on"fluorescent probes and its detection of iodide ion in aqueous environment
g-CNQDs@H Ig2+"on-off-on"fluorescent probe is successfully prepared using mercury ion as a bridge and graphite phase carbon nitride quantum dots(g-CNQDs)as a precursor,and applied to the recognition and detection of I-in water.The optimal response times for Hg2+to g-CNQDs and I-to g-CNQDs@Hg2+fluorescent probes are 180 s and 60 s,respectively,when the buffer solution of boric acid-potassium chloride-sodium hydroxide solution is used and pH value is 7.4.Under the optimal experimental conditions,the fluorescence intensity of g-CNQDs@Hg2+ shows a significant linear relationship with the concentration of I- in the range of 0.89～89 μmol·L-1,and the detection limit of I-is 0.35 μmol·L-1.The results show that the g-CNQDs@Hg2+fluo-rescent probe has high selectivity and sensitivity to I-.The average recoveries of I- in tap water and salt are 87.7％and 84.26％,respectively,which meet the analytical requirements for I-detection in real samples.
carbon nitride quantum dotsfluorescence probemercury ioniodide ion
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