Yu Zhaochuan, Ma Wenhui, Wu Tao, Wen Jing, Zhang Yong, Wang Liyan, He Yuqian, Chu Hongtao, Hu Minggang
College of Chemistry and Chemical Engineering and College of Materials Science and Engineering, Qiqihar University, 42 Wenhua avenue, Qiqihar 161006, China.
ACS Omega. 2020 Mar 25;5(13):7369-7378. doi: 10.1021/acsomega.9b04387. eCollection 2020 Apr 7.
In this work, coumarin derivatives (C) are used to enhance the fluorescence of graphene quantum dots (GQDs) by covalently linking the carboxyl groups on the edge of the GQD sheet. The as-synthesized coumarin-modified graphene quantum dots (C-GQDs) have a uniform particle size with an average diameter of 3.6 nm. Simultaneously, the C-GQDs have strong fluorescence emission, excellent photostability, and high fluorescence quantum yield. C-GQDs and CN can form a C-GQDs+CN system due to deprotonation and/or intermolecular interactions. The introduced hydroquinone (HQ) is oxidized to benzoquinone (BQ), and the interaction between BQ and the C-GQDs+CN system could lead to fluorescence enhancement of C-GQDs. Meanwhile, the redox reaction between BQ and ascorbic acid (AA) can be used for quantitative detection of AA with CN and HQ being used as substrates. Based on the above mechanism, C-GQDs are developed as a multicomponent detection and sensing platform, and the detection limits for CN, HQ, and AA were 4.7, 2.2, and 2.2 nM, respectively. More importantly, satisfactory results were obtained when the platform was used to detect CN, HQ, and AA in living cells and fresh fruits.
在本工作中，香豆素衍生物（C）通过与石墨烯量子点（GQDs）片边缘的羧基共价连接来增强其荧光。合成的香豆素修饰的石墨烯量子点（C-GQDs）具有均匀的粒径，平均直径为3.6 nm。同时，C-GQDs具有强荧光发射、优异的光稳定性和高荧光量子产率。由于去质子化和/或分子间相互作用，C-GQDs和CN可以形成C-GQDs+CN体系。引入的对苯二酚（HQ）被氧化为苯醌（BQ），BQ与C-GQDs+CN体系之间的相互作用可导致C-GQDs的荧光增强。同时，BQ与抗坏血酸（AA）之间的氧化还原反应可用于以CN和HQ为底物对AA进行定量检测。基于上述机理，C-GQDs被开发为一种多组分检测和传感平台，对CN、HQ和AA的检测限分别为4.7、2.2和2.2 nM。更重要的是，当该平台用于检测活细胞和新鲜水果中的CN、HQ和AA时，获得了令人满意的结果。
