Microwave assisted one-pot synthesis of graphene quantum dots as highly sensitive fluorescent probes for detection of iron ions and pH value

• Graphene quantum dots (GQDs) were synthesized by microwave-assisted pyrolysis of aspartic acid.
• GQDs can serve as a fluorescent probe for sensitive detection of Fe3+ and pH value.
• GQDs can be directly used for live cells imaging.

Recently, carbon nanomaterials have received considerable attention as fluorescent probes owing to their low toxicity, water solubility and stable photochemical properties. However, the development of graphene quantum dots (GQDs) is still on its early stage. In this work, GQDs were successfully synthesized by one-step microwave assisted pyrolysis of aspartic acid (Asp) and NH4HCO3 mixture. The as-prepared GQDs exhibited strongly blue fluorescence with high quantum yield up to 14%. Strong fluorescence quenching effect of Fe3+ on GQDs can be used for its high selectivity detection among of general metal ions. The probe exhibited a wide linear response concentration range (0–50 μM) to Fe3+ and the limit of detection (LOD) was calculated to be 0.26 μM. In addition, GQDs are also sensitive to the pH value in the range from 2 to 12 indicating a great potential as optical pH sensors. More importantly, the GQDs possess lower cellular toxicity and high photostability and can be directly used as fluorescent probes for cell imaging.

Aspartic acid-derived graphene quantum dots show great sensing property for Fe3+, pH value and bioimaging as fluorescent probes.Figure optionsDownload as PowerPoint slide