Highly passivated phosphorous and nitrogen co-doped carbon quantum dots and fluorometric assay for detection of copper ions
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Carbon quantum dots are becoming powerful fluorophore materials for metal ion analysis. Here, highly passivated green phosphorous and nitrogen co-doped carbon quantum dots (C-dots) were prepared using low-temperature carbonization route. Strong green fluorescence emission around 490 nm and excitation wavelength independent C-dots were obtained. Morphological, surface, and optical properties of the C-dots were characterized. Fluorescence emission of C-dots was quenched selectively by copper ions and restored by adding copper chelators, such as EDTA and sulfide ions. Thus, C-dots were successfully used for direct determination of copper ions. Detection limit as low as 1.5 nM (s/n = 3) was achieved for copper ions. Such a low detection limit is very significant for metal analysis using our proposed facile method and low-cost substrates. Experimental results showed that the prepared C-dots demonstrated high sensitivity and selectivity for Cu2+ ion detection and the method is robust and rugged.
KeywordsCarbon quantum dots Copper Fluorimetric assay Phosphorous and nitrogen-doped carbon quantum dots
The author thanks Dr. Hugo Celio for his help with the XPS measurement at the University of Texas at Austin.
The author thanks the University of Sulaimani and Ministry of Higher Education and Scientific Research in Kurdistan for supporting the work.
Compliance with ethical standards
Conflict of interest
The author declares that there is no conflict of interest.
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