The robustness of graphene quantum dots (GQDs) production, using a bottom-up approach, using citric acid (non-functionalized GQDs) or citric acid/glutathione (N-doped GQDs) as precursors, were studied to evaluate variations in the optical properties of these nanomaterials as a function of the experimental conditions (precursor proportion, heating rate, and hydro-exfoliating medium). Three different types of GQDs were prepared to compare, mainly, the photoluminescent responses and their suppression by Fe3+. Non-functionalized GQDs showed intense photoluminescence (wavelength of excitation = 330 nm and wavelength of emission in the range of 450-460 nm). The GQDs prepared in basic condition medium showed luminescence property up to four times greater (wavelength of emission in the same region). The GQDs-GSH showed a luminescent response up to two orders of magnitude higher (wavelength of excitation = 347 nm and wavelength of emission = 425 nm), and their interaction with Fe3+, used as a mediator for the quantification of ascorbic acid (AA), produced suppression of the original signal and wavelength of emission shift to 440 nm. The variation in the proportions of glutathione and ascorbic acid did not imply significant differences in the general characteristics of these GQDs-GSH, pointing to the robustness of their preparation conditions. The addition of Fe3+ (4.0 × 10-4 mol L-1) reduced the original signal by half, allowing to distinguish the recovery of the signal caused by the addition of AA. The normalized analytical curves for AA showed linearity in the concentration range between 1.0 × 10-5 and 1.0 × 10-4 mol L-1. Analysis of a real sample produced recovery affected by analyte instability in the probe environment.