A novel "on-off-on" fluorescent sensor for 6-thioguanine and Hg2+ based on g-C3N4 nanosheets

作者:Duan, Junling; Zhang, Yuanhong; Yin, Yanbin; Li, Houshen; Wang, Jun*; Zhu, Lusheng*
来源:Sensors and Actuators B: Chemical , 2018, 257: 504-510.
DOI:10.1016/j.snb.2017.10.071

摘要

A facile fluorescence "on-off-on" approach for sensing 6-Thioguanine (6-TG) and Hg2+ was designed based on g-C3N4 nanosheets. It was found that in the absence of Hg2+, the addition of 6-TG to g-C3N4 nanosheets solution resulted in the fluorescence quenching of g-C3N4 nanosheets (turn off). However, in the presence of Hg2+, the quenched fluorescence of g-C3N4 nanosheets was recovered ( turn on), because the high affinity of Hg2+ and 6-TG resulted in the loss of molecular interactions between 6-TG and g-C3N4 nanosheets. The quantitative detection of 6-TG was obtained via the fluorescence quenching of g-C3N4 nanosheets with a detection limit of 65 nM. Meantime, the 6-TG-g-C3N4 nanosheets system could be used as a fluorescent "turn on" sensor for Hg2+. The detection limit for Hg2+ was 37 nM. The proposed method showed high selectivity for the detection of 6-TG and Hg2+. In addition, it was successfully applied to detect Hg2+ in real water samples.