One-step hydrothermal synthesis of 4-Metylimidazole Decorated Carbon Nanoparticles and Their Fluorescence Enhancement Sensing of Heavy Metal Ions

We report fluorescent carbon nanoparticle decorated with 4-methylimidazole (4-MEI) prepared by a one-step hydrothermal synthesis. Upon binding to toxic heavy metals including Hg2+ and Cd2+, the fluorescence emission displayed notable enhancement. This is in contrast with the majority of other one-step synthesized fluorescent carbon nanoparticle sensing systems which exhibit quenching, due to the non-radiative energy transfer. In comparison, the decorated 4-MEI on the carbon nanoparticles prevents the non-radiative energy transfer when the analytes bind to the 4-MEI. Further results on the fluorescence responses on the removal of the surface decorated 4-MEI and re-coordination of a reference 4-MEI against the same metal ions suggested that the 4-MEI on the carbon nanoparticles’ surface plays a key role in the observed fluorescence enhancement. These features indicate an immense potential for further development of CNP based fluorescence enhancement sensing platforms for effective detection of analytes of interests.