Graphene quantum dots decorated with magnetic nanoparticles: Synthesis, electrodeposition, characterization and application as an electrochemical sensor towards determination of some amino acids at physiological pH

This study reports on the synthesis and characterization of a novel nano-composite, Fe₃O₄ magnetic nanoparticles/graphene quantum dots (Fe₃O₄ MNP-GQDs), for sensing of some amino acids. For the first time, as-synthesized GQDs and Fe₃O₄ MNPs-GQDs was electrodeposited on the glassy carbon electrode (GCE) by cyclic voltammetry (CV) regime in the potential range from − 1.0 to 1.0 V. Fe₃O₄ MNP-GQDs is engineered to specifically and effectively capture and enhancement the electrochemical signals of some amino acids at physiological pH due to the synergy among GQDs and magnetic nanoparticles. We have illustrated that the obtained Fe₃O₄ MNPs-GQDs exhibited a much higher electroactivity individual GQDs and Fe₃O₄ MNPs for the electrooxidation and detection of amino acid which was about 10 fold higher than for GQDs. Magnetic and specific properties of the Fe₃O₄ MNP-GQDs can be exploited to capture and pre-concentration the amino acids onto its surface, which are important for detection of multi-amino acids. - Highlights: • Electrooxidation of amino acids was performed using Fe₃O₄ MNP-GQDs. • Modified electrode shows new advantages as an amino acids sensor. • Excellent electrocatalytic activity was obtained for amino acids oxidation.