Magnetic Graphene Quantum Dots as a Functional Nanomaterial Towards Voltammetric Detection of L-tryptophan at Physiological pH

L-Tryptophan (L-Trp) is of great importance in the biochemical, pharmaceutical and dietetic fields as it is precursor molecule of some hormones, neurotransmitters and other relevant biomolecules. So, determination of this amino acid has important role in detection of some neuron based disease. The main purpose of this report was to develop application of Fe3O4 magnetic nanoparticles/graphene quantum dots (Fe3O4 MNP-GQDs)) as a nanosensor towards electrooxidation and determination of L-Trp and also the evaluation its kinetic parameters. In continuation of our efforts to use Fe3O4 MNP-GQDs for amino acids detection, our objective in the present work was to expand application of this sensor for the determination of L-Trp which is very sensitive. Decrease in oxidation overpotential and enhancement in current proved the electrocatalytic activity of Fe3O4 MNPs-GQDs-GCE as a sensor. Importantly, by this simple method of fabrication a much lower detection limit was achieved without involving any pre-treatment or activation steps. The analytical applicability of the modified electrode has been evaluated by successfully employing it for the determination of L-Trp in the standard solution.