Selective sensing of explosive nitrophenol compounds by using hydrophobic carbon nanoparticles

Abstract

Nitroaromatic compounds (NACs) have been polluting the soil and groundwater via anthropogenic activities. Due to their well-known explosive and toxic nature, their selective-sensitive detection specifically 2,4,6-trinitrophenol (TNP) and 2,4-dinitrophenol (DNP) become essential. Herein, hydrophobic carbon nanoparticles (HCNPs) have been synthesized by a single-step and simple methodology by refluxing maleic acid in the presence of oleylamine. The as-synthesized HCNPs possess a spherical shape with a diameter of 60 ± 5 nm and is insoluble in an aqueous medium but soluble in non-aqueous solvents. HCNPs show brightly blue emission at ∼464 nm with ∼24% quantum yield. The fluorescence property of HCNPs is applied towards the selective sensing of NACs. The fluorescence intensities of HCNPs have been significantly quenched selectively only after the addition of TNP and DNP from the tested many NACs. The detection limit of HCNPs for TNP and DNP is low as ∼242 nM and ∼276 nM, respectively. Concerning the plausible mechanism of selective fluorescence-based detection, TNP/DNP molecules interact with HCNPs, which involves the dynamic quenching behavior with both the Förster resonance energy transfer (FRET) and photo-induced electron transfer (PET) process.