Synthesis of high fluorescence graphene quantum dots and their selective detection for Fe3+ in aqueous solution

In recent years, carbon particles have gained numerous attentions because of their simple synthetic process, low toxicity and water solubility. The present work involves synthesis of two types of graphene quantum dots (GQDs) by treating sulfydryl group (−SH) amino acid glutathione (GSH) in the presence and absence of AgNO 3 via one pot route, respectively. The Ag + ions from AgNO 3 can combine the −SH from GSH to form Ag 2 S, thus surfaces of the obtained graphene quantum dots (N-GQDs) are mainly modified by some free hydroxyl groups ( OH), amino groups ( NH 2 ) and carboxyl groups ( COOH). In the absence of Ag + ions, the surfaces of as-prepared graphene quantum dots (SN-GQDs) not only include OH, NH 2 and COOH, but also −SH. Interestingly, as-prepared two kinds of GQDs both have strong fluorescence with different emission wavelength. More importantly, these GQDs have special recognition ability for metal ions. The N-GQDs respond rapidly towards the presence of Fe 3+ ions, and can be used as a probe to detect Fe 3+ ions in waste water, while the SN-GQDs have a special recognition to Hg 2+ ions.