A green path to extract carbon quantum dots by coconut water: Another fluorescent probe towards Fe3+ ions

Abstract

In recent years, carbon quantum dots (CQDs) have been of great enthrallment in the fluorescent probe field. Carbon precursors with interesting physicochemical properties may be derived from natural sources. In this research, for the first time, coconut water has been used as a source of carbon to prepare blue fluorescent CQDs without any modification and functionalization. The preparation of CQDs is very simple and cost-effective, when compared with other conventional techniques. The reaction parameters temperature and pH were varied to obtain monodispersed spherical CQDs with an average grain size of ∼5nm. The CQDs exhibit blue emission with a wavelength of 487nm with an excitation wavelength of 390nm and are used for Fe3+ ions detection. Fe3+ ions have been observed to quench the fluorescence intensity of the CQDs than other heavy metals. In the presence of Fe3+ ions, the fluorescent CQDs are quenched due to the interaction of CQDs and Fe3+ ions. A spectroscopic result shows that Fe3+ ions can be observed within a concentration of 0–700μM, as well as the detection limit is 0.30μM. The CQDs provide a unique pathway for potential application in the environmental monitoring of heavy metal ions.