Sulfur-doped graphene quantum dot-based paper sensor for highly sensitive and selective detection of 4-nitrophenol in contaminated water and wastewater

• Published in: RSC advances 2019-08, Vol.9 (46), p.26588-26597
• Main Authors: Ngoc Anh, Nguyen Thi, Chang, Pei-Yi, Doong, Ruey-An
• Format: Article
• Language: English
• Subjects: Chemistry; Citric acid; Deionization; Fluorescent indicators; Graphene; Nitrophenol; Pollutants; Pyrolysis; Quantum dots; Sulfur; Ultraviolet radiation; Wastewater
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c9ra04414k

4-Nitrophenol (4-NP) is a promulgated priority pollutant, which can cause a negative impact on human health. The development of a direct and effective technique for the rapid detection and screening of 4-NP is, therefore, of urgent need. In this study, the blue luminescent sulfur-doped graphene quantum dots (S-GQDs) with a size of 1-5 nm are fabricated using a one-step pyrolysis procedure in the presence of citric acid and 3-mercaptosuccinic acid. The S-GQDs exhibit a strong emission band at 450 nm under the excitation of 330 nm UV light. 4-NP can serve as the fluorescence quencher by the π-π interaction with S-GQD, resulting in the linear decrease in fluorescence intensity after the addition of various 4-NP concentrations ranging from 10 nM to 200 μM. The S-GQDs serve as the sensing probe to enhance the analytical performance on 4-NP detection with the limit of detection values of 0.7 and 3.5 nM in deionized water and wastewater, respectively. The S-GQD based sensing platform can be used to detect 4-NP in different matrices of water and wastewater. In addition, the detected percentages of spiked 4-NP concentrations in the presence of different matrices and interferences are in the range of (98 ± 5)-(108 ± 2)%. Moreover, the S-GQD based paper sensor can rapidly screen 4-NP in wastewater within 1 min. Results obtained in this study clearly demonstrate the superiority of S-GQDs as a promising fluorescence probe for highly sensitive and selective detection of a wide concentration range of 4-NP in deionized water and wastewater. Sulfur-doped graphene quantum dots have been prepared for effective and rapid detection of 4-nitrophenol.