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Ultraspeed synthesis of highly fluorescent N‐doped carbon dots for the label‐free detection of manganese ( VII )
Author(s) -
Mohammed Areef,
Gugulothu Yaku,
Bandi Rajkumar,
Dadigala Ramakrishna,
Utkoor Umesh Kumar
Publication year - 2021
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.202000545
Subject(s) - chemistry , fluorescence , detection limit , x ray photoelectron spectroscopy , analytical chemistry (journal) , spectroscopy , fourier transform infrared spectroscopy , quenching (fluorescence) , fluorescence spectroscopy , photobleaching , nuclear chemistry , aqueous solution , photochemistry , chromatography , organic chemistry , chemical engineering , physics , quantum mechanics , engineering
Here, we report ultraspeed preparation of highly emissive nitrogen‐doped carbon dots (NCDs) using threonine and guanidine hydrochloride by the microwave irradiation method. Experimental conditions such as microwave power, irradiation time, and reactant ratio were varied to achieve high‐quality NCDs. NCDs were thoroughly characterized using transmission electron microscopy, X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, UV–visible spectroscopy, and fluorescence spectroscopy. NCDs presented high aqueous solubility, bright emission with a quantum yield of 30%, and excitation‐dependent emission. Investigation of optical properties unveiled their admirable characters of tolerance to photobleaching, high salinity, pH, and long shelf life. Evaluation of their metal ion detection ability unveiled their selective fluorescence quenching response to Mn (VII), and further explorations revealed the application of NCDs as a label‐free probe for Mn (VII) detection. The probe presented a good linear response ( R 2 = 0.992) in the concentration range of 5–35 μM with a detection limit of 0.66 μM. Mechanistic studies disclosed that the inner filter effect was responsible for fluorescence quenching. The probe presented no significant interference and was successfully applied for the quantification of Mn (VII) in spiked real‐water samples.