Synthesis of Nitrogen-Doped Graphene Quantum Dots at Low Temperature for Electrochemical Sensing Trinitrotoluene

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• 作者：Zhewei Cai ; Fumin Li ; Ping Wu ; Lijuan Ji ; Hui Zhang ; Chenxin Cai ; Dominic F. Gervasio
• 刊名：Analytical Chemistry
• 出版年：2015
• 出版时间：December 1, 2015
• 年：2015
• 卷：87
• 期：23
• 页码：11803-11811
• 全文大小：445K
• ISSN：1520-6882

文摘

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 鈭?.5 nm with an N/C atomic ratio of up to 鈭?.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 鈭?.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 卤 7 mA mM^鈥? cm^鈥?. 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.