Synthesis of Mo, N-doped carbon dots for the fluorescence detection of Cr ₂ O ₇ ²⁻ and luteolin and their application in anti-counterfeiting

In this work, Mo, N-doped carbon dots (Mo, N-CDs) were synthesized <i>via</i> a one-step hydrothermal method using l-arginine, ammonium molybdate and 1-pyrenecarboxaldehyde as precursors. The synthetic conditions, morphological structure, elemental composition and optical properties of Mo, N-CDs were carefully optimized and characterized. The as-synthesized Mo, N-CDs displayed cyan fluorescence emission at 494 nm with a high quantum yield (41.5%) and demonstrated superior pH stability, salt tolerance, thermostability and photobleaching resistance. In addition, Mo, N-CDs were employed as "on-off" sensors for the detection of Cr₂O₇ ^2- and luteolin with excellent linear correlation over a wide linear range (0-50 μM and 0-45 μM, respectively), low detection limits (0.96 μM and 0.64 μM, respectively) and short response time (<10 s). In addition, the practical detection of Cr₂O₇ ^2- and luteolin in actual samples demonstrated good recoveries (93-110%) with relative standard deviations less than 5%. Furthermore, the Mo, N-CD aqueous solution was directly used as a fluorescent ink and exhibited excellent anti-counterfeiting effects.