Department of Chemical & Environmental Engineering, University of Arizona , 1133 East James E. Rogers Way, Tucson, Arizona 85721, United States.
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.
Anal Chem. 2015 Dec 1;87(23):11803-11. doi: 10.1021/acs.analchem.5b03201. Epub 2015 Nov 18.
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.
氮掺杂石墨烯量子点（N-GQDs）在低温下合成，作为一种新的催化剂，可用于电化学检测 2,4,6-三硝基甲苯（TNT）。N-GQDs 通过氧化超声处理氧化石墨烯（GO）形成纳米级物质，然后通过与联氨反应进行化学还原和氮掺杂。合成的 N-GQDs 的平均直径约为 2.5nm，N/C 原子比高达约 6.4%。为了检测 TNT，首先将 TNT 溶液中的 N-GQDs/GC 电极在 0V 下保持 150s，通过在电极上积累 TNT。然后，将含有 TNT 的 N-GQDs/GC 电极转移到新鲜的 PBS 溶液（0.1M，pH7.0，不含 TNT）中，在 LSV 中，在-0.36V 下 TNT 的还原电流对水溶液中 TNT 浓度从 1 到 400ppb 呈线性响应，相关系数为 0.999，信噪比为 3 时检测限为 0.2ppb，检测灵敏度为 363±7mA mM(-1) cm(-2)。该新方法检测 TNT 的检测限为 0.2ppb，远低于美国环保署规定的饮用水中 TNT 的 2ppb 限值。因此，N-GQDs 允许电化学方法用于检测饮用水中的 TNT，以确定 TNT 水平是否安全。
