Economical, green route to highly fluorescence intensity carbon materials based on ligninsulfonate/graphene quantum dots composites: Application as excellent fluorescent sensing platform for detection of Fe3+ ions

A facile, economical, and green method has been developed to prepare a new fluorescent sensor based on ligninsulfonate/graphene quantum dots (SL/GQDs) core/shell hybrids for label-free sensitive and selective detection of Fe 3+ . The combination of these two materials brings both excellent photoluminescent properties (the fluorescence intensity of SL/GQDs composites is four times higher than the free GQDs) and nice selectivity. In this composite, SL molecule plays two key roles in the system as a π-rich and sulfur-incorporated compound to enhance the fluorescence and as a chelator to detect Fe 3+ . The obtained sensor presents excellent sensitivity and selectivity toward Fe 3+ and exhibits a good linearity in the range of 0.005–500   μM with a detection limit as low as 0.5   nM. We have further explored the practical use of such proposed probe for Fe 3+ determination in lake water samples, which shows promise in environmental determination.