A novel 'on-off-on; fluorescent sensor for 6-thioguanine and Hg~(2+) based on g-C_3N_4 nanosheets

摘要

Graphical abstractDisplay OmittedHighlights•A novel “on-off-on” fluorescent sensor was designed based on g-C3N4nanosheets.•Dual detection of 6-thioguanine and Hg2+can be obtained based on this sensor.•For 6-thioguanine detection, a new fluorescent sensor was developed.•For Hg2+detection, a novel “turn on” fluorescent sensor was developed.•The sensor exhibited high sensitivity and selectivity.AbstractA facile fluorescence “on-off-on” approach for sensing 6-Thioguanine (6-TG) and Hg2+was designed based on g-C3N4nanosheets. It was found that in the absence of Hg2+, the addition of 6-TG to g-C3N4nanosheets solution resulted in the fluorescence quenching of g-C3N4nanosheets (turn off). However, in the presence of Hg2+, the quenched fluorescence of g-C3N4nanosheets 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-C3N4nanosheets. The quantitative detection of 6-TG was obtained via the fluorescence quenching of g-C3N4nanosheets with a detection limit of 65nM. Meantime, the 6-TG-g-C3N4nanosheets system could be used as a fluorescent “turn on” sensor for Hg2+. The detection limit for Hg2+was 37nM. 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.