Highly selective and sensitive fluorescent determination of Fe3+ within alcoholic beverages with 1,5-diphenylcarbazone-functionalized graphene quantum dots

•Graphene quantum dots were functionalized and made selective toward detection of Fe3+.•Graphene quantum dots were highly crystalline and of monomodal size distribution.•Electron-transfer is proposed as the mechanism involved in the detection of Fe3+.•Chemical and instrumental optimizations maximized the selectivity and sensitivity.•Fe3+ was determined in white wine samples, a novel sample for this type of probe.