One-pot synthesis of N-doped graphene quantum dots as highly sensitive fluorescent sensor for detection of mercury ions water solutions

Abstract

A facile hydrothermal approach was taken to synthesize environmental-friendly and water-soluble fluorescence N-doped graphene quantum dots (N-GQDs) by using citric acid and ethylenediamine as the reactants. The photoluminescence properties of N-GQDs were investigated and applied to determine the trace of Hg2+ in aqueous solution. The fluorescence of N-GQDs was dramatically quenched after the addition of Hg2+. This is due to the efficient charge transfer and coordination interaction between N-GQDs and mercury ions. The N-GQDs base fluorescence sensor exhibit excellently selective and sensitive response to Hg2+. According to the standard curve analysis, a two-stage liner response to Hg2+ can be obtained in the concentration ranging from 1 nM to 1000 nM. The detection limits (LOD) were calculated as 0.45 and 67.3 nM, respectively, which could satisfy the requirements of Hg2+ detection in water. The fluorescence N-GQDs presented here provides a functional platform with low detection limit, excellent selectivity and high sensitivity.