Department of Chemistry
Green synthesis of fluorescent nitrogen/sulfur-doped carbon dots and investigation of their properties by HPLC coupled with mass spectrometry
A fast and green approach to synthesise ultrasmall nitrogen (N) and sulfur (S)-doped carbon dots (N,S-C-dots) by microwave-assisted pyrolysis of the precursors rice as carbon source and N-acetyl-l-cysteine (NAC) as N and S dopant has been developed. The obtained N,S-C-dots were fully characterised by elemental analysis, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, UV-vis absorption and photoluminescence (PL) spectroscopy. The undoped C-dots (derived from rice only) and N,S-C-dots possess different chemical compositions, sizes and spectral properties. With the assistance of high-performance liquid chromatography coupled with fluorescence detection (HPLC-FD), the effect of different mass ratios of NAC to rice (NAC/rice) on N,S-C-dots was investigated. Higher NAC/rice ratio benefits the generation of N,S-C-dots with stronger fluorescence emission. In addition, the HPLC separated N,S-C-dots fractions were collected and further characterised by mass spectrometry, UV-vis absorption and PL spectroscopy, showing that the structural changes induced by doping with heteroatoms N and S plays a key role in regulating the PL properties of the N,S-C-dots. This work highlights the merits of synthesising N,S-C-dots from readily available natural bioresources and applying modern HPLC-FD technology to study the effect of doped heteroatoms on N,S-C-dots properties. © 2014 The Partner Organisations.
Source Publication Title
Royal Society of Chemistry
Hu, Qin, Man Chin Paau, Yan Zhang, Xiaojuan Gong, Lei Zhang, Dongtao Lu, Yang Liu, Qiaoling Liu, Jun Yao, and Martin M. F. Choi. "Green synthesis of fluorescent nitrogen/sulfur-doped carbon dots and investigation of their properties by HPLC coupled with mass spectrometry." RSC Advances 4.35 (2014): 18065-18073.