title: "On-Off-On" fluorescence sensor based on g-C3N4nanosheets for selective and sequential detection of Ag+and S2.
abstract: Detection of silver (Ag+) and sulfide (S2-) ions is important because their presence in large amounts can cause many diseases. In this study, a novel, simple, "on-off-on" fluorescence sensor based on g-C3N4nanosheets for sequential detection of Ag+and S2-was designed. The fluorescence signal of the g-C3N4nanosheets is quenched because Ag+chelates with the N of the g-C3N4nanosheets, leading to photoinduced electron transfer from the sheets to Ag+. After adding S2-, the fluorescence of the g-C3N4nanosheets is recovered due to formation of Ag2S, which activates the fluorescence of the g-C3N4nanosheets. The recovery efficiency was found to increase with increasing concentrations of S2-, with linear calibration ranging from 0nmol/L to 30nmol/L. Other potentially interfering species, such as SO42-, PO43-, HPO42-, H2PO4-, CO32-, NO3-, Ac-, and HCO3-, presented negligible effects on S2-detection. Moreover, the proposed sensor exhibited several advantages, including low cost, easy preparation, rapid detection, excellent biocompatibility, and a switchable fluorescence response. These attributes make this fluorescent sensor a promising tool for environmental applications.
authors.affiliation: School of Chemistry and Chemical Engineering of Xianyang Normal University, Xianyang 712000, PR China; School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164, United States. Electronic address: shanwang2002@163.com.
authors.forename: Shan
authors.initials: S
authors.lastname: Wang
authors.affiliation: School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164, United States.
authors.forename: Qian
authors.initials: Q
authors.lastname: Lu
authors.affiliation: School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164, United States.
authors.forename: Xu
authors.initials: X
authors.lastname: Yan
authors.affiliation: School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164, United States.
authors.forename: Mingming
authors.initials: M
authors.lastname: Yang
authors.affiliation: School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164, United States.
authors.forename: Ranfeng
authors.initials: R
authors.lastname: Ye
authors.affiliation: School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164, United States.
authors.forename: Dan
authors.initials: D
authors.lastname: Du
authors.affiliation: School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164, United States. Electronic address: yuehe.lin@wsu.edu.
authors.forename: Yuehe
authors.initials: Y
authors.lastname: Lin
keywords: Ag(+); Fluorescence; G-C(3)N(4) nanosheets; S(2−); Sensor