Green and cost-effective fluorescent carbon nanoparticles for the selective and sensitive detection of iron (III) ions in aqueous solution: Mechanistic insights and cell line imaging studies

In this work, a simple, green and cost-effective fluorescence based analytical procedure using water soluble carbon nanoparticles (CNPs) is described for selective and sensitive detection of Iron (III) (i.e. ferric (Fe3+)) ions in water. The CNPs were synthesized by acid treatment of naturally occurring D-glucose followed by heating at 80 degrees C. The fluorescence intensity of the CNPs (excited at 360 nm) was found to decrease with the increase in concentration of Fe3+ ions. The fluorescence lifetime of CNPs remained unchanged with increasing Fe3+ concentration, suggesting the quenching to be static. The zeta potential which was negative for CNPs became positive on addition of Fe3+, thus indicating the adsorption of Fe3+ on CNPs surface. The sensing of Fe3+ by CNPs was also observed in-vivo using DLD cells. The limit of quantification and limit of detection of Fe3+ ions were found to be 18 ppm and as 56.0 ppb, respectively. Validation of the proposed fluorescence quenching based technique was achieved by comparing with Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). (C) 2015 Elsevier B.V. All rights reserved.