Amino functionalized graphene quantum dots - new fluorescent sensor for Co2+ ions

Abstract

Graphene quantum dots (GQDs) were fabricated by simple electrochemical oxidation of graphite electrodes. Modified GQDs were obtained by gamma irradiation of GQDs, EDA, and IPA mixture at a dose of 25 kGy. In this approach, GQDs with the amino groups were produced (25γ-GQDs). These GQDs have shown a high uniformity, good dispersibility in water, and strong photoluminescence in the blue part of the electromagnetic spectrum. Modified GQDs were studied in the optical detection of Co2+ ions. The PL intensities of GQDs were measured in the presence of Co2+ ions in the concentration range 0-7.5 µmol L-1. It was demonstrated that PL intensities decreased linearly in the concentration range 0-2.5 µmol L-1. The value of the coefficient of determination (R2= 0.95949) indicates the potential of 25γ-GQDs for application in optical sensing of Co2+ ions.