Red-emissive nitrogen doped carbon quantum dots for highly selective and sensitive fluorescence detection of the alachlor herbicide in soil samples

Red-emissive nitrogen doped carbon quantum dots (N-CQDs) were synthesized by a facile and efficient microwave-assisted hydrothermal treatment of p-phenylenediamine (p-PD), and then applied for the highly selective and sensitive fluorescence detection of the alachlor herbicide in soil samples. The synthesized N-CQDs exhibited strong red emission with a 27.6% quantum yield (QY) and high stability. Under the optimized experimental conditions, the as-prepared red-emissive N-CQDs were employed as a fluorescent probe to successfully detect trace alachlor, and their fluorescence presented a good linear decline with the increase of the alachlor concentration from 0.005 to 150 μM with a limit of detection of 0.2 nM. The N-CQDs as a fluorescent probe were used for the detection of alachlor in soil samples with satisfactory recoveries ranging from 86.6–114.3%, indicating that they were a promising fluorescent probe for highly selective and sensitive determination of alachlor.