A hybrid of carbon dots with 4-chloro-7-nitro-2,1,3-benzoxadiazole for selective detection of p-phenylenediamine

• Published in: Environmental science. Nano Vol. 4; no. 5; pp. 1037 - 1044
• Main Authors: Wang, Wen-Jing, Xia, Jun-Mei, Hai, Xin, Chen, Ming-Li, Wang, Jian-Hua
• Format: Journal Article
• Language: English
• Published: 01.05.2017
• ISSN: 2051-8153; 2051-8161
• DOI: 10.1039/C7EN00027H

The nucleophilic substitution reaction between 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD-Cl) and –NH 2 groups on amino-functionalized carbon dots (CDs) produces a novel carbon dot-based hybrid, CDs@NBD for short. In addition to the characteristic fluorescence emission of carbon dots at λ ex / λ em = 360/443 nm, the CDs@NBD hybrid gives rise to new photoluminescence at λ ex / λ em = 460/544 nm, which is significantly quenched by p -phenylenediamine (PPD) via static quenching. This provides a novel sensing approach for fluorometric detection of PPD with CDs@NBD as a probe. A linear calibration graph is obtained within two concentration ranges of 0.1–1.0 μmol L −1 and 1.0–10.0 μmol L −1 , along with a detection limit of 56 nmol L −1 and a RSD of <3% (at 1.0 μmol L −1 ). The common coexisting species in environmental and biological sample matrices cause no obvious interferences on the detection of PPD. The colour change of the CDs@NBD hybrid solution with the variation in PPD concentration also facilitates visual detection of PPD, which further demonstrates promising applications in environmental and biological sample analysis.