Preparation of n-doped carbon quantum dots for the detection of PA in real explosion dust samples

Nitrogen doping carbon quantum dots (N-CQDs) are synthesized using o-phenylenediamine as a carbon and nitrogen source via the water hydrothermal method. The size of the obtained N-CQDs is about 5.51 nm, and FTIR results show that their surface contains many –OH and –NH2 groups. N-CQDs can selectively recognize PA and its homologous (DNP and NP) in the presence of other analytes (including TNT, Tetryl, PETN, RDX, HMX, NC, NG, DNT, NT, NB, DNP, NP, BP, PC, AN, Ca2+, Cl-, Mg2+, Na+, H2O2). A linear correlation is also observed between PA concentration (0 ∼ 10.0 μmol/L) and N-CQDs fluorescence intensity (0.05 mg/mL) at 556 nm. The linear curve is y = -3.64 × 107x + 404.91, and the detection limit is ∼ 70 nmol/L. The Stern-Volmer graphs lack sufficient linearity, confirming the static quenching interaction between N-CQDs and PA. Finally, the N-CQDs are successfully applied to determine PA content in simulated and real samples quantitatively.