Solvent-free synthesis of sulfur- and nitrogen-co-doped fluorescent carbon nanoparticles from glutathione for highly selective and sensitive detection of mercury(II) ions

•A simple, low-cost, green and solvent-free method is developed for preparation of water-soluble fluorescent SNCNs.•Glutathione is used as a single precursor for SNCNs by solid-phase thermal treatment.•SNCNs have a bright blue fluorescence and high quantum yield of 39.9%.•SNCNs serve as a fluorescent probe for detection of Hg2+ with high sensitivity and selectivity.

In this report, a simple, low-cost, green, and solvent-free method was developed to prepare sulfur- and nitrogen-co-doped carbon nanoparticles (SNCNs) by one-pot solid-phase thermal treatment of glutathione, with the nitrogen and sulfur contents of 16.1% and 2.0%, respectively. SNCNs show bright blue photoluminescence with a high quantum yield of 39.9%, which is significantly quenched by trace Hg2+ via the Hg2+-thiol interactions and extended for label-free fluorescent detection of Hg2+ with high selectivity and sensitivity, even with high concentrations of interference (i.e., other metal ions). The fluorescence intensity increases linearly with Hg2+ from 1.0 nM to 50.0 μM, with the detection limit of 0.05 nM (S/N = 3).

Graphical abstractWe reported a simple, direct, green and solvent-free method for preparation of sulfur- and nitrogen-co-doped fluorescent carbon nanoparticles (SNCNs) by one-pot solid-phase thermal treatment of glutathione. The fluorescence can be quenched significantly by trace Hg2+ via the high-affinity of Hg2+ with thiol group of SNCNs. The as-prepared SNCNs are used as an effective fluorescent sensing platform for lable-free detection of Hg2+ with high sensitivity and selectivity.Figure optionsDownload full-size imageDownload as PowerPoint slide