title: Synthesis of Nitrogen-Doped Graphene Quantum Dots at Low Temperature for Electrochemical Sensing Trinitrotoluene.
abstract: Nitrogen-doped graphene quantum dots (N-GQDs) are synthesized at low temperature as a new catalyst allowing electrochemical detection of 2,4,6-trinitrotoluene (TNT). N-GQDs are made by an oxidative ultrasonication of graphene oxide (GO) forming nanometer-sized species, which are then chemically reduced and nitrogen doped by reacting with hydrazine. The as-synthesized N-GQDs have an average diameter of ∼2.5 nm with an N/C atomic ratio of up to ∼6.4%. To detect TNT, TNT is first accumulated on N-GQDs modified glassy carbon (N-GQDs/GC) electrode by holding the electrode at a 0 V versus Ag/AgCl for 150 s in an aqueous TNT solution. Next, the N-GQDs/GC electrode with accumulated TNT is transferred to a fresh PBS solution (0.1 M, pH 7.0, without TNT), where the TNT reduction current at -0.36 V versus Ag/AgCl in a linear scan voltammogram (LSV) shows a linear response to TNT concentration in the aqueous solution from 1 to 400 ppb, with a correlation coefficient of 0.999, a detection limit of 0.2 ppb at a signal/noise (S/N) of 3, and a detection sensitivity of 363 ± 7 mA mM(-1) cm(-2). The detection limit of 0.2 ppb of TNT for this new method is much lower than 2 ppb set by the U.S. Environmental Protection Agency for drinking water. Therefore, N-GQDs allow an electrochemical method for assaying TNT in drinking water to determine if levels of TNT are safe or not.
authors.affiliation: Department of Chemical & Environmental Engineering, University of Arizona , 1133 East James E. Rogers Way, Tucson, Arizona 85721, United States.
authors.forename: Zhewei
authors.initials: Z
authors.lastname: Cai
authors.affiliation: Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, National and Local Joint Engineering Research Center of Biomedical Functional Materials, College of Chemistry and Materials Science, Nanjing Normal University , Nanjing 210097, P.R. China.
authors.forename: Fumin
authors.initials: F
authors.lastname: Li
authors.affiliation: Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, National and Local Joint Engineering Research Center of Biomedical Functional Materials, College of Chemistry and Materials Science, Nanjing Normal University , Nanjing 210097, P.R. China.
authors.forename: Ping
authors.initials: P
authors.lastname: Wu
authors.affiliation: Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, National and Local Joint Engineering Research Center of Biomedical Functional Materials, College of Chemistry and Materials Science, Nanjing Normal University , Nanjing 210097, P.R. China.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Ji
authors.affiliation: Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, National and Local Joint Engineering Research Center of Biomedical Functional Materials, College of Chemistry and Materials Science, Nanjing Normal University , Nanjing 210097, P.R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Jiangsu Key Laboratory of New Power Batteries, Jiangsu Collaborative Innovation Center of Biomedical Functional Materials, National and Local Joint Engineering Research Center of Biomedical Functional Materials, College of Chemistry and Materials Science, Nanjing Normal University , Nanjing 210097, P.R. China.
authors.forename: Chenxin
authors.initials: C
authors.lastname: Cai
authors.affiliation: Department of Chemical & Environmental Engineering, University of Arizona , 1133 East James E. Rogers Way, Tucson, Arizona 85721, United States.
authors.forename: Dominic F
authors.initials: DF
authors.lastname: Gervasio
mesh_terms: D000327:Adsorption; D055664:Electrochemical Techniques; D006108:Graphite / Q000737:chemistry*; D009584:Nitrogen / Q000737:chemistry*; D010087:Oxides / Q000138:chemical synthesis / Q000737:chemistry; D010316:Particle Size; D045663:Quantum Dots; D013499:Surface Properties; D013696:Temperature; D014303:Trinitrotoluene / Q000032:analysis*
chemical_list: D010087:Oxides; D014303:Trinitrotoluene; D006108:Graphite; D009584:Nitrogen