Carbon Dots-Based Fluorescent Sensor for Glyphosate Detection Via Fe³⁺-Mediated Fluorescence Quenching and Recovery

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Carbon dots (CDs) are fluorescent nanomaterials with diverse applications.
• Hydrothermal carbonization is a common method for synthesizing CDs.
• Developing sensitive and selective sensors for environmental pollutants is crucial.

Purpose of the Study:

• To synthesize and characterize four types of carbon dots (CDs) using different carbon sources.
• To investigate the influence of precursors on CD properties, particularly fluorescence.
• To develop a sensitive sensor for detecting the herbicide glyphosate in water.

Main Methods:

• Synthesis of CDs via hydrothermal carbonization using ascorbic, citric, maleic, or succinic acid with ammonium citrate.
• Characterization using fluorescence, UV-Vis, Raman spectroscopy, TEM, FTIR, and XRD.
• Development and optimization of an "off-on" fluorescence sensor for Fe3+ ions and glyphosate detection.

Main Results:

• CDs with sizes ranging from 1.7-2.8 nm were synthesized, showing excitation-dependent emission.
• CDs derived from succinic acid and ammonium citrate (SAC) demonstrated high selectivity and sensitivity for Fe3+ ions (LOD 0.37 μM).
• An "off-on" sensor for glyphosate was developed with a low limit of detection (LOD) of 0.59 μM, applicable to real water samples.

Conclusions:

• Precursor choice significantly impacts CD fluorescence properties and sensing capabilities.
• The developed SAC-based CD sensor offers a rapid, cost-effective, and environmentally friendly method for glyphosate detection.
• This technology holds promise for monitoring herbicides in aquatic environments.